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Posted to commits@myfaces.apache.org by hn...@apache.org on 2021/01/26 19:20:38 UTC

[myfaces-tobago] 01/02: TOBAGO-1932: Refactor Bootstrap Theme Building (fix datepicker)

This is an automated email from the ASF dual-hosted git repository.

hnoeth pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/myfaces-tobago.git

commit c7c922d7bb22a370a0f3be48b32dfa6a27cc5872
Author: Udo Schnurpfeil <ud...@irian.eu>
AuthorDate: Thu Jan 21 18:55:13 2021 +0100

    TOBAGO-1932: Refactor Bootstrap Theme Building (fix datepicker)
    
    * Datepicker doesn't work correctly with the newer
      rollup plugin for node-resolve
---
 .../tobago-theme-standard/npm/dist/js/tobago.js    | 2548 +++++++++++++++++++-
 .../tobago-theme-standard/npm/package-lock.json    |   68 +-
 .../tobago-theme-standard/npm/package.json         |    2 +-
 .../tobago-theme-standard/npm/rollup.config.js     |    5 +-
 4 files changed, 2582 insertions(+), 41 deletions(-)

diff --git a/tobago-theme/tobago-theme-standard/npm/dist/js/tobago.js b/tobago-theme/tobago-theme-standard/npm/dist/js/tobago.js
index 4637fda..58ac087 100644
--- a/tobago-theme/tobago-theme-standard/npm/dist/js/tobago.js
+++ b/tobago-theme/tobago-theme-standard/npm/dist/js/tobago.js
@@ -1,12 +1,7 @@
-(function (global, factory) {
-    typeof exports === 'object' && typeof module !== 'undefined' ? factory(require('vanillajs-datepicker/js/Datepicker.js')) :
-    typeof define === 'function' && define.amd ? define(['vanillajs-datepicker/js/Datepicker.js'], factory) :
-    (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.Datepicker));
-}(this, (function (Datepicker) { 'use strict';
-
-    function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }
-
-    var Datepicker__default = /*#__PURE__*/_interopDefaultLegacy(Datepicker);
+(function (factory) {
+    typeof define === 'function' && define.amd ? define(factory) :
+    factory();
+}((function () { 'use strict';
 
     /*
      * Licensed to the Apache Software Foundation (ASF) under one or more
@@ -2274,6 +2269,2537 @@
         }
     });
 
+    function hasProperty(obj, prop) {
+      return Object.prototype.hasOwnProperty.call(obj, prop);
+    }
+
+    function lastItemOf(arr) {
+      return arr[arr.length - 1];
+    }
+
+    // push only the items not included in the array
+    function pushUnique(arr, ...items) {
+      items.forEach((item) => {
+        if (arr.includes(item)) {
+          return;
+        }
+        arr.push(item);
+      });
+      return arr;
+    }
+
+    function stringToArray(str, separator) {
+      // convert empty string to an empty array
+      return str ? str.split(separator) : [];
+    }
+
+    function isInRange(testVal, min, max) {
+      const minOK = min === undefined || testVal >= min;
+      const maxOK = max === undefined || testVal <= max;
+      return minOK && maxOK;
+    }
+
+    function limitToRange(val, min, max) {
+      if (val < min) {
+        return min;
+      }
+      if (val > max) {
+        return max;
+      }
+      return val;
+    }
+
+    function createTagRepeat(tagName, repeat, attributes = {}, index = 0, html = '') {
+      const openTagSrc = Object.keys(attributes).reduce((src, attr) => {
+        let val = attributes[attr];
+        if (typeof val === 'function') {
+          val = val(index);
+        }
+        return `${src} ${attr}="${val}"`;
+      }, tagName);
+      html += `<${openTagSrc}></${tagName}>`;
+
+      const next = index + 1;
+      return next < repeat
+        ? createTagRepeat(tagName, repeat, attributes, next, html)
+        : html;
+    }
+
+    // Remove the spacing surrounding tags for HTML parser not to create text nodes
+    // before/after elements
+    function optimizeTemplateHTML(html) {
+      return html.replace(/>\s+/g, '>').replace(/\s+</, '<');
+    }
+
+    function stripTime(timeValue) {
+      return new Date(timeValue).setHours(0, 0, 0, 0);
+    }
+
+    function today() {
+      return new Date().setHours(0, 0, 0, 0);
+    }
+
+    // Get the time value of the start of given date or year, month and day
+    function dateValue(...args) {
+      switch (args.length) {
+        case 0:
+          return today();
+        case 1:
+          return stripTime(args[0]);
+      }
+
+      // use setFullYear() to keep 2-digit year from being mapped to 1900-1999
+      const newDate = new Date(0);
+      newDate.setFullYear(...args);
+      return newDate.setHours(0, 0, 0, 0);
+    }
+
+    function addDays(date, amount) {
+      const newDate = new Date(date);
+      return newDate.setDate(newDate.getDate() + amount);
+    }
+
+    function addWeeks(date, amount) {
+      return addDays(date, amount * 7);
+    }
+
+    function addMonths(date, amount) {
+      // If the day of the date is not in the new month, the last day of the new
+      // month will be returned. e.g. Jan 31 + 1 month → Feb 28 (not Mar 03)
+      const newDate = new Date(date);
+      const monthsToSet = newDate.getMonth() + amount;
+      let expectedMonth = monthsToSet % 12;
+      if (expectedMonth < 0) {
+        expectedMonth += 12;
+      }
+
+      const time = newDate.setMonth(monthsToSet);
+      return newDate.getMonth() !== expectedMonth ? newDate.setDate(0) : time;
+    }
+
+    function addYears(date, amount) {
+      // If the date is Feb 29 and the new year is not a leap year, Feb 28 of the
+      // new year will be returned.
+      const newDate = new Date(date);
+      const expectedMonth = newDate.getMonth();
+      const time = newDate.setFullYear(newDate.getFullYear() + amount);
+      return expectedMonth === 1 && newDate.getMonth() === 2 ? newDate.setDate(0) : time;
+    }
+
+    // Calculate the distance bettwen 2 days of the week
+    function dayDiff(day, from) {
+      return (day - from + 7) % 7;
+    }
+
+    // Get the date of the specified day of the week of given base date
+    function dayOfTheWeekOf(baseDate, dayOfWeek, weekStart = 0) {
+      const baseDay = new Date(baseDate).getDay();
+      return addDays(baseDate, dayDiff(dayOfWeek, weekStart) - dayDiff(baseDay, weekStart));
+    }
+
+    // Get the ISO week of a date
+    function getWeek(date) {
+      // start of ISO week is Monday
+      const thuOfTheWeek = dayOfTheWeekOf(date, 4, 1);
+      // 1st week == the week where the 4th of January is in
+      const firstThu = dayOfTheWeekOf(new Date(thuOfTheWeek).setMonth(0, 4), 4, 1);
+      return Math.round((thuOfTheWeek - firstThu) / 604800000) + 1;
+    }
+
+    // Get the start year of the period of years that includes given date
+    // years: length of the year period
+    function startOfYearPeriod(date, years) {
+      /* @see https://en.wikipedia.org/wiki/Year_zero#ISO_8601 */
+      const year = new Date(date).getFullYear();
+      return Math.floor(year / years) * years;
+    }
+
+    // pattern for format parts
+    const reFormatTokens = /dd?|DD?|mm?|MM?|yy?(?:yy)?/;
+    // pattern for non date parts
+    const reNonDateParts = /[\s!-/:-@[-`{-~年月日]+/;
+    // cache for persed formats
+    let knownFormats = {};
+    // parse funtions for date parts
+    const parseFns = {
+      y(date, year) {
+        return new Date(date).setFullYear(parseInt(year, 10));
+      },
+      m(date, month, locale) {
+        const newDate = new Date(date);
+        let monthIndex = parseInt(month, 10) - 1;
+
+        if (isNaN(monthIndex)) {
+          if (!month) {
+            return NaN;
+          }
+
+          const monthName = month.toLowerCase();
+          const compareNames = name => name.toLowerCase().startsWith(monthName);
+          // compare with both short and full names because some locales have periods
+          // in the short names (not equal to the first X letters of the full names)
+          monthIndex = locale.monthsShort.findIndex(compareNames);
+          if (monthIndex < 0) {
+            monthIndex = locale.months.findIndex(compareNames);
+          }
+          if (monthIndex < 0) {
+            return NaN;
+          }
+        }
+
+        newDate.setMonth(monthIndex);
+        return newDate.getMonth() !== normalizeMonth(monthIndex)
+          ? newDate.setDate(0)
+          : newDate.getTime();
+      },
+      d(date, day) {
+        return new Date(date).setDate(parseInt(day, 10));
+      },
+    };
+    // format functions for date parts
+    const formatFns = {
+      d(date) {
+        return date.getDate();
+      },
+      dd(date) {
+        return padZero(date.getDate(), 2);
+      },
+      D(date, locale) {
+        return locale.daysShort[date.getDay()];
+      },
+      DD(date, locale) {
+        return locale.days[date.getDay()];
+      },
+      m(date) {
+        return date.getMonth() + 1;
+      },
+      mm(date) {
+        return padZero(date.getMonth() + 1, 2);
+      },
+      M(date, locale) {
+        return locale.monthsShort[date.getMonth()];
+      },
+      MM(date, locale) {
+        return locale.months[date.getMonth()];
+      },
+      y(date) {
+        return date.getFullYear();
+      },
+      yy(date) {
+        return padZero(date.getFullYear(), 2).slice(-2);
+      },
+      yyyy(date) {
+        return padZero(date.getFullYear(), 4);
+      },
+    };
+
+    // get month index in normal range (0 - 11) from any number
+    function normalizeMonth(monthIndex) {
+      return monthIndex > -1 ? monthIndex % 12 : normalizeMonth(monthIndex + 12);
+    }
+
+    function padZero(num, length) {
+      return num.toString().padStart(length, '0');
+    }
+
+    function parseFormatString(format) {
+      if (typeof format !== 'string') {
+        throw new Error("Invalid date format.");
+      }
+      if (format in knownFormats) {
+        return knownFormats[format];
+      }
+
+      // sprit the format string into parts and seprators
+      const separators = format.split(reFormatTokens);
+      const parts = format.match(new RegExp(reFormatTokens, 'g'));
+      if (separators.length === 0 || !parts) {
+        throw new Error("Invalid date format.");
+      }
+
+      // collect format functions used in the format
+      const partFormatters = parts.map(token => formatFns[token]);
+
+      // collect parse function keys used in the format
+      // iterate over parseFns' keys in order to keep the order of the keys.
+      const partParserKeys = Object.keys(parseFns).reduce((keys, key) => {
+        const token = parts.find(part => part[0] !== 'D' && part[0].toLowerCase() === key);
+        if (token) {
+          keys.push(key);
+        }
+        return keys;
+      }, []);
+
+      return knownFormats[format] = {
+        parser(dateStr, locale) {
+          const dateParts = dateStr.split(reNonDateParts).reduce((dtParts, part, index) => {
+            if (part.length > 0 && parts[index]) {
+              const token = parts[index][0];
+              if (token === 'M') {
+                dtParts.m = part;
+              } else if (token !== 'D') {
+                dtParts[token] = part;
+              }
+            }
+            return dtParts;
+          }, {});
+
+          // iterate over partParserkeys so that the parsing is made in the oder
+          // of year, month and day to prevent the day parser from correcting last
+          // day of month wrongly
+          return partParserKeys.reduce((origDate, key) => {
+            const newDate = parseFns[key](origDate, dateParts[key], locale);
+            // ingnore the part failed to parse
+            return isNaN(newDate) ? origDate : newDate;
+          }, today());
+        },
+        formatter(date, locale) {
+          let dateStr = partFormatters.reduce((str, fn, index) => {
+            return str += `${separators[index]}${fn(date, locale)}`;
+          }, '');
+          // separators' length is always parts' length + 1,
+          return dateStr += lastItemOf(separators);
+        },
+      };
+    }
+
+    function parseDate(dateStr, format, locale) {
+      if (dateStr instanceof Date || typeof dateStr === 'number') {
+        const date = stripTime(dateStr);
+        return isNaN(date) ? undefined : date;
+      }
+      if (!dateStr) {
+        return undefined;
+      }
+      if (dateStr === 'today') {
+        return today();
+      }
+
+      if (format && format.toValue) {
+        const date = format.toValue(dateStr, format, locale);
+        return isNaN(date) ? undefined : stripTime(date);
+      }
+
+      return parseFormatString(format).parser(dateStr, locale);
+    }
+
+    function formatDate(date, format, locale) {
+      if (isNaN(date) || (!date && date !== 0)) {
+        return '';
+      }
+
+      const dateObj = typeof date === 'number' ? new Date(date) : date;
+
+      if (format.toDisplay) {
+        return format.toDisplay(dateObj, format, locale);
+      }
+
+      return parseFormatString(format).formatter(dateObj, locale);
+    }
+
+    const listenerRegistry = new WeakMap();
+    const {addEventListener, removeEventListener} = EventTarget.prototype;
+
+    // Register event listeners to a key object
+    // listeners: array of listener definitions;
+    //   - each definition must be a flat array of event target and the arguments
+    //     used to call addEventListener() on the target
+    function registerListeners(keyObj, listeners) {
+      let registered = listenerRegistry.get(keyObj);
+      if (!registered) {
+        registered = [];
+        listenerRegistry.set(keyObj, registered);
+      }
+      listeners.forEach((listener) => {
+        addEventListener.call(...listener);
+        registered.push(listener);
+      });
+    }
+
+    function unregisterListeners(keyObj) {
+      let listeners = listenerRegistry.get(keyObj);
+      if (!listeners) {
+        return;
+      }
+      listeners.forEach((listener) => {
+        removeEventListener.call(...listener);
+      });
+      listenerRegistry.delete(keyObj);
+    }
+
+    // Event.composedPath() polyfill for Edge
+    // based on https://gist.github.com/kleinfreund/e9787d73776c0e3750dcfcdc89f100ec
+    if (!Event.prototype.composedPath) {
+      const getComposedPath = (node, path = []) => {
+        path.push(node);
+
+        let parent;
+        if (node.parentNode) {
+          parent = node.parentNode;
+        } else if (node.host) { // ShadowRoot
+          parent = node.host;
+        } else if (node.defaultView) {  // Document
+          parent = node.defaultView;
+        }
+        return parent ? getComposedPath(parent, path) : path;
+      };
+
+      Event.prototype.composedPath = function () {
+        return getComposedPath(this.target);
+      };
+    }
+
+    function findFromPath(path, criteria, currentTarget, index = 0) {
+      const el = path[index];
+      if (criteria(el)) {
+        return el;
+      } else if (el === currentTarget || !el.parentElement) {
+        // stop when reaching currentTarget or <html>
+        return;
+      }
+      return findFromPath(path, criteria, currentTarget, index + 1);
+    }
+
+    // Search for the actual target of a delegated event
+    function findElementInEventPath(ev, selector) {
+      const criteria = typeof selector === 'function' ? selector : el => el.matches(selector);
+      return findFromPath(ev.composedPath(), criteria, ev.currentTarget);
+    }
+
+    // default locales
+    const locales = {
+      en: {
+        days: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
+        daysShort: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
+        daysMin: ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"],
+        months: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
+        monthsShort: ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"],
+        today: "Today",
+        clear: "Clear",
+        titleFormat: "MM y"
+      }
+    };
+
+    // config options updatable by setOptions() and their default values
+    const defaultOptions = {
+      autohide: false,
+      beforeShowDay: null,
+      beforeShowDecade: null,
+      beforeShowMonth: null,
+      beforeShowYear: null,
+      calendarWeeks: false,
+      clearBtn: false,
+      dateDelimiter: ',',
+      datesDisabled: [],
+      daysOfWeekDisabled: [],
+      daysOfWeekHighlighted: [],
+      defaultViewDate: undefined, // placeholder, defaults to today() by the program
+      disableTouchKeyboard: false,
+      format: 'mm/dd/yyyy',
+      language: 'en',
+      maxDate: null,
+      maxNumberOfDates: 1,
+      maxView: 3,
+      minDate: null,
+      nextArrow: '»',
+      orientation: 'auto',
+      pickLevel: 0,
+      prevArrow: '«',
+      showDaysOfWeek: true,
+      showOnClick: true,
+      showOnFocus: true,
+      startView: 0,
+      title: '',
+      todayBtn: false,
+      todayBtnMode: 0,
+      todayHighlight: false,
+      updateOnBlur: true,
+      weekStart: 0,
+    };
+
+    const range = document.createRange();
+
+    function parseHTML(html) {
+      return range.createContextualFragment(html);
+    }
+
+    function hideElement(el) {
+      if (el.style.display === 'none') {
+        return;
+      }
+      // back up the existing display setting in data-style-display
+      if (el.style.display) {
+        el.dataset.styleDisplay = el.style.display;
+      }
+      el.style.display = 'none';
+    }
+
+    function showElement(el) {
+      if (el.style.display !== 'none') {
+        return;
+      }
+      if (el.dataset.styleDisplay) {
+        // restore backed-up dispay property
+        el.style.display = el.dataset.styleDisplay;
+        delete el.dataset.styleDisplay;
+      } else {
+        el.style.display = '';
+      }
+    }
+
+    function emptyChildNodes(el) {
+      if (el.firstChild) {
+        el.removeChild(el.firstChild);
+        emptyChildNodes(el);
+      }
+    }
+
+    function replaceChildNodes(el, newChildNodes) {
+      emptyChildNodes(el);
+      if (newChildNodes instanceof DocumentFragment) {
+        el.appendChild(newChildNodes);
+      } else if (typeof newChildNodes === 'string') {
+        el.appendChild(parseHTML(newChildNodes));
+      } else if (typeof newChildNodes.forEach === 'function') {
+        newChildNodes.forEach((node) => {
+          el.appendChild(node);
+        });
+      }
+    }
+
+    const {
+      language: defaultLang,
+      format: defaultFormat,
+      weekStart: defaultWeekStart,
+    } = defaultOptions;
+
+    // Reducer function to filter out invalid day-of-week from the input
+    function sanitizeDOW(dow, day) {
+      return dow.length < 6 && day >= 0 && day < 7
+        ? pushUnique(dow, day)
+        : dow;
+    }
+
+    function calcEndOfWeek(startOfWeek) {
+      return (startOfWeek + 6) % 7;
+    }
+
+    // validate input date. if invalid, fallback to the original value
+    function validateDate(value, format, locale, origValue) {
+      const date = parseDate(value, format, locale);
+      return date !== undefined ? date : origValue;
+    }
+
+    // Validate viewId. if invalid, fallback to the original value
+    function validateViewId(value, origValue, max = 3) {
+      const viewId = parseInt(value, 10);
+      return viewId >= 0 && viewId <= max ? viewId : origValue;
+    }
+
+    // Create Datepicker configuration to set
+    function processOptions(options, datepicker) {
+      const inOpts = Object.assign({}, options);
+      const config = {};
+      const locales = datepicker.constructor.locales;
+      let {
+        format,
+        language,
+        locale,
+        maxDate,
+        maxView,
+        minDate,
+        pickLevel,
+        startView,
+        weekStart,
+      } = datepicker.config || {};
+
+      if (inOpts.language) {
+        let lang;
+        if (inOpts.language !== language) {
+          if (locales[inOpts.language]) {
+            lang = inOpts.language;
+          } else {
+            // Check if langauge + region tag can fallback to the one without
+            // region (e.g. fr-CA → fr)
+            lang = inOpts.language.split('-')[0];
+            if (locales[lang] === undefined) {
+              lang = false;
+            }
+          }
+        }
+        delete inOpts.language;
+        if (lang) {
+          language = config.language = lang;
+
+          // update locale as well when updating language
+          const origLocale = locale || locales[defaultLang];
+          // use default language's properties for the fallback
+          locale = Object.assign({
+            format: defaultFormat,
+            weekStart: defaultWeekStart
+          }, locales[defaultLang]);
+          if (language !== defaultLang) {
+            Object.assign(locale, locales[language]);
+          }
+          config.locale = locale;
+          // if format and/or weekStart are the same as old locale's defaults,
+          // update them to new locale's defaults
+          if (format === origLocale.format) {
+            format = config.format = locale.format;
+          }
+          if (weekStart === origLocale.weekStart) {
+            weekStart = config.weekStart = locale.weekStart;
+            config.weekEnd = calcEndOfWeek(locale.weekStart);
+          }
+        }
+      }
+
+      if (inOpts.format) {
+        const hasToDisplay = typeof inOpts.format.toDisplay === 'function';
+        const hasToValue = typeof inOpts.format.toValue === 'function';
+        const validFormatString = reFormatTokens.test(inOpts.format);
+        if ((hasToDisplay && hasToValue) || validFormatString) {
+          format = config.format = inOpts.format;
+        }
+        delete inOpts.format;
+      }
+
+      //*** dates ***//
+      // while min and maxDate for "no limit" in the options are better to be null
+      // (especially when updating), the ones in the config have to be undefined
+      // because null is treated as 0 (= unix epoch) when comparing with time value
+      let minDt = minDate;
+      let maxDt = maxDate;
+      if (inOpts.minDate !== undefined) {
+        minDt = inOpts.minDate === null
+          ? dateValue(0, 0, 1)  // set 0000-01-01 to prevent negative values for year
+          : validateDate(inOpts.minDate, format, locale, minDt);
+        delete inOpts.minDate;
+      }
+      if (inOpts.maxDate !== undefined) {
+        maxDt = inOpts.maxDate === null
+          ? undefined
+          : validateDate(inOpts.maxDate, format, locale, maxDt);
+        delete inOpts.maxDate;
+      }
+      if (maxDt < minDt) {
+        minDate = config.minDate = maxDt;
+        maxDate = config.maxDate = minDt;
+      } else {
+        if (minDate !== minDt) {
+          minDate = config.minDate = minDt;
+        }
+        if (maxDate !== maxDt) {
+          maxDate = config.maxDate = maxDt;
+        }
+      }
+
+      if (inOpts.datesDisabled) {
+        config.datesDisabled = inOpts.datesDisabled.reduce((dates, dt) => {
+          const date = parseDate(dt, format, locale);
+          return date !== undefined ? pushUnique(dates, date) : dates;
+        }, []);
+        delete inOpts.datesDisabled;
+      }
+      if (inOpts.defaultViewDate !== undefined) {
+        const viewDate = parseDate(inOpts.defaultViewDate, format, locale);
+        if (viewDate !== undefined) {
+          config.defaultViewDate = viewDate;
+        }
+        delete inOpts.defaultViewDate;
+      }
+
+      //*** days of week ***//
+      if (inOpts.weekStart !== undefined) {
+        const wkStart = Number(inOpts.weekStart) % 7;
+        if (!isNaN(wkStart)) {
+          weekStart = config.weekStart = wkStart;
+          config.weekEnd = calcEndOfWeek(wkStart);
+        }
+        delete inOpts.weekStart;
+      }
+      if (inOpts.daysOfWeekDisabled) {
+        config.daysOfWeekDisabled = inOpts.daysOfWeekDisabled.reduce(sanitizeDOW, []);
+        delete inOpts.daysOfWeekDisabled;
+      }
+      if (inOpts.daysOfWeekHighlighted) {
+        config.daysOfWeekHighlighted = inOpts.daysOfWeekHighlighted.reduce(sanitizeDOW, []);
+        delete inOpts.daysOfWeekHighlighted;
+      }
+
+      //*** multi date ***//
+      if (inOpts.maxNumberOfDates !== undefined) {
+        const maxNumberOfDates = parseInt(inOpts.maxNumberOfDates, 10);
+        if (maxNumberOfDates >= 0) {
+          config.maxNumberOfDates = maxNumberOfDates;
+          config.multidate = maxNumberOfDates !== 1;
+        }
+        delete inOpts.maxNumberOfDates;
+      }
+      if (inOpts.dateDelimiter) {
+        config.dateDelimiter = String(inOpts.dateDelimiter);
+        delete inOpts.dateDelimiter;
+      }
+
+      //*** pick level & view ***//
+      let newPickLevel = pickLevel;
+      if (inOpts.pickLevel !== undefined) {
+        newPickLevel = validateViewId(inOpts.pickLevel, 2);
+        delete inOpts.pickLevel;
+      }
+      if (newPickLevel !== pickLevel) {
+        pickLevel = config.pickLevel = newPickLevel;
+      }
+
+      let newMaxView = maxView;
+      if (inOpts.maxView !== undefined) {
+        newMaxView = validateViewId(inOpts.maxView, maxView);
+        delete inOpts.maxView;
+      }
+      // ensure max view >= pick level
+      newMaxView = pickLevel > newMaxView ? pickLevel : newMaxView;
+      if (newMaxView !== maxView) {
+        maxView = config.maxView = newMaxView;
+      }
+
+      let newStartView = startView;
+      if (inOpts.startView !== undefined) {
+        newStartView = validateViewId(inOpts.startView, newStartView);
+        delete inOpts.startView;
+      }
+      // ensure pick level <= start view <= max view
+      if (newStartView < pickLevel) {
+        newStartView = pickLevel;
+      } else if (newStartView > maxView) {
+        newStartView = maxView;
+      }
+      if (newStartView !== startView) {
+        config.startView = newStartView;
+      }
+
+      //*** template ***//
+      if (inOpts.prevArrow) {
+        const prevArrow = parseHTML(inOpts.prevArrow);
+        if (prevArrow.childNodes.length > 0) {
+          config.prevArrow = prevArrow.childNodes;
+        }
+        delete inOpts.prevArrow;
+      }
+      if (inOpts.nextArrow) {
+        const nextArrow = parseHTML(inOpts.nextArrow);
+        if (nextArrow.childNodes.length > 0) {
+          config.nextArrow = nextArrow.childNodes;
+        }
+        delete inOpts.nextArrow;
+      }
+
+      //*** misc ***//
+      if (inOpts.disableTouchKeyboard !== undefined) {
+        config.disableTouchKeyboard = 'ontouchstart' in document && !!inOpts.disableTouchKeyboard;
+        delete inOpts.disableTouchKeyboard;
+      }
+      if (inOpts.orientation) {
+        const orientation = inOpts.orientation.toLowerCase().split(/\s+/g);
+        config.orientation = {
+          x: orientation.find(x => (x === 'left' || x === 'right')) || 'auto',
+          y: orientation.find(y => (y === 'top' || y === 'bottom')) || 'auto',
+        };
+        delete inOpts.orientation;
+      }
+      if (inOpts.todayBtnMode !== undefined) {
+        switch(inOpts.todayBtnMode) {
+          case 0:
+          case 1:
+            config.todayBtnMode = inOpts.todayBtnMode;
+        }
+        delete inOpts.todayBtnMode;
+      }
+
+      //*** copy the rest ***//
+      Object.keys(inOpts).forEach((key) => {
+        if (inOpts[key] !== undefined && hasProperty(defaultOptions, key)) {
+          config[key] = inOpts[key];
+        }
+      });
+
+      return config;
+    }
+
+    const pickerTemplate = optimizeTemplateHTML(`<div class="datepicker">
+  <div class="datepicker-picker">
+    <div class="datepicker-header">
+      <div class="datepicker-title"></div>
+      <div class="datepicker-controls">
+        <button type="button" class="%buttonClass% prev-btn"></button>
+        <button type="button" class="%buttonClass% view-switch"></button>
+        <button type="button" class="%buttonClass% next-btn"></button>
+      </div>
+    </div>
+    <div class="datepicker-main"></div>
+    <div class="datepicker-footer">
+      <div class="datepicker-controls">
+        <button type="button" class="%buttonClass% today-btn"></button>
+        <button type="button" class="%buttonClass% clear-btn"></button>
+      </div>
+    </div>
+  </div>
+</div>`);
+
+    const daysTemplate = optimizeTemplateHTML(`<div class="days">
+  <div class="days-of-week">${createTagRepeat('span', 7, {class: 'dow'})}</div>
+  <div class="datepicker-grid">${createTagRepeat('span', 42)}</div>
+</div>`);
+
+    const calendarWeeksTemplate = optimizeTemplateHTML(`<div class="calendar-weeks">
+  <div class="days-of-week"><span class="dow"></span></div>
+  <div class="weeks">${createTagRepeat('span', 6, {class: 'week'})}</div>
+</div>`);
+
+    // Base class of the view classes
+    class View {
+      constructor(picker, config) {
+        Object.assign(this, config, {
+          picker,
+          element: parseHTML(`<div class="datepicker-view"></div>`).firstChild,
+          selected: [],
+        });
+        this.init(this.picker.datepicker.config);
+      }
+
+      init(options) {
+        if (options.pickLevel !== undefined) {
+          this.isMinView = this.id === options.pickLevel;
+        }
+        this.setOptions(options);
+        this.updateFocus();
+        this.updateSelection();
+      }
+
+      // Execute beforeShow() callback and apply the result to the element
+      // args:
+      // - current - current value on the iteration on view rendering
+      // - timeValue - time value of the date to pass to beforeShow()
+      performBeforeHook(el, current, timeValue) {
+        let result = this.beforeShow(new Date(timeValue));
+        switch (typeof result) {
+          case 'boolean':
+            result = {enabled: result};
+            break;
+          case 'string':
+            result = {classes: result};
+        }
+
+        if (result) {
+          if (result.enabled === false) {
+            el.classList.add('disabled');
+            pushUnique(this.disabled, current);
+          }
+          if (result.classes) {
+            const extraClasses = result.classes.split(/\s+/);
+            el.classList.add(...extraClasses);
+            if (extraClasses.includes('disabled')) {
+              pushUnique(this.disabled, current);
+            }
+          }
+          if (result.content) {
+            replaceChildNodes(el, result.content);
+          }
+        }
+      }
+    }
+
+    class DaysView extends View {
+      constructor(picker) {
+        super(picker, {
+          id: 0,
+          name: 'days',
+          cellClass: 'day',
+        });
+      }
+
+      init(options, onConstruction = true) {
+        if (onConstruction) {
+          const inner = parseHTML(daysTemplate).firstChild;
+          this.dow = inner.firstChild;
+          this.grid = inner.lastChild;
+          this.element.appendChild(inner);
+        }
+        super.init(options);
+      }
+
+      setOptions(options) {
+        let updateDOW;
+
+        if (hasProperty(options, 'minDate')) {
+          this.minDate = options.minDate;
+        }
+        if (hasProperty(options, 'maxDate')) {
+          this.maxDate = options.maxDate;
+        }
+        if (options.datesDisabled) {
+          this.datesDisabled = options.datesDisabled;
+        }
+        if (options.daysOfWeekDisabled) {
+          this.daysOfWeekDisabled = options.daysOfWeekDisabled;
+          updateDOW = true;
+        }
+        if (options.daysOfWeekHighlighted) {
+          this.daysOfWeekHighlighted = options.daysOfWeekHighlighted;
+        }
+        if (options.todayHighlight !== undefined) {
+          this.todayHighlight = options.todayHighlight;
+        }
+        if (options.weekStart !== undefined) {
+          this.weekStart = options.weekStart;
+          this.weekEnd = options.weekEnd;
+          updateDOW = true;
+        }
+        if (options.locale) {
+          const locale = this.locale = options.locale;
+          this.dayNames = locale.daysMin;
+          this.switchLabelFormat = locale.titleFormat;
+          updateDOW = true;
+        }
+        if (options.beforeShowDay !== undefined) {
+          this.beforeShow = typeof options.beforeShowDay === 'function'
+            ? options.beforeShowDay
+            : undefined;
+        }
+
+        if (options.calendarWeeks !== undefined) {
+          if (options.calendarWeeks && !this.calendarWeeks) {
+            const weeksElem = parseHTML(calendarWeeksTemplate).firstChild;
+            this.calendarWeeks = {
+              element: weeksElem,
+              dow: weeksElem.firstChild,
+              weeks: weeksElem.lastChild,
+            };
+            this.element.insertBefore(weeksElem, this.element.firstChild);
+          } else if (this.calendarWeeks && !options.calendarWeeks) {
+            this.element.removeChild(this.calendarWeeks.element);
+            this.calendarWeeks = null;
+          }
+        }
+        if (options.showDaysOfWeek !== undefined) {
+          if (options.showDaysOfWeek) {
+            showElement(this.dow);
+            if (this.calendarWeeks) {
+              showElement(this.calendarWeeks.dow);
+            }
+          } else {
+            hideElement(this.dow);
+            if (this.calendarWeeks) {
+              hideElement(this.calendarWeeks.dow);
+            }
+          }
+        }
+
+        // update days-of-week when locale, daysOfweekDisabled or weekStart is changed
+        if (updateDOW) {
+          Array.from(this.dow.children).forEach((el, index) => {
+            const dow = (this.weekStart + index) % 7;
+            el.textContent = this.dayNames[dow];
+            el.className = this.daysOfWeekDisabled.includes(dow) ? 'dow disabled' : 'dow';
+          });
+        }
+      }
+
+      // Apply update on the focused date to view's settings
+      updateFocus() {
+        const viewDate = new Date(this.picker.viewDate);
+        const viewYear = viewDate.getFullYear();
+        const viewMonth = viewDate.getMonth();
+        const firstOfMonth = dateValue(viewYear, viewMonth, 1);
+        const start = dayOfTheWeekOf(firstOfMonth, this.weekStart, this.weekStart);
+
+        this.first = firstOfMonth;
+        this.last = dateValue(viewYear, viewMonth + 1, 0);
+        this.start = start;
+        this.focused = this.picker.viewDate;
+      }
+
+      // Apply update on the selected dates to view's settings
+      updateSelection() {
+        const {dates, rangepicker} = this.picker.datepicker;
+        this.selected = dates;
+        if (rangepicker) {
+          this.range = rangepicker.dates;
+        }
+      }
+
+       // Update the entire view UI
+      render() {
+        // update today marker on ever render
+        this.today = this.todayHighlight ? today() : undefined;
+        // refresh disabled dates on every render in order to clear the ones added
+        // by beforeShow hook at previous render
+        this.disabled = [...this.datesDisabled];
+
+        const switchLabel = formatDate(this.focused, this.switchLabelFormat, this.locale);
+        this.picker.setViewSwitchLabel(switchLabel);
+        this.picker.setPrevBtnDisabled(this.first <= this.minDate);
+        this.picker.setNextBtnDisabled(this.last >= this.maxDate);
+
+        if (this.calendarWeeks) {
+          // start of the UTC week (Monday) of the 1st of the month
+          const startOfWeek = dayOfTheWeekOf(this.first, 1, 1);
+          Array.from(this.calendarWeeks.weeks.children).forEach((el, index) => {
+            el.textContent = getWeek(addWeeks(startOfWeek, index));
+          });
+        }
+        Array.from(this.grid.children).forEach((el, index) => {
+          const classList = el.classList;
+          const current = addDays(this.start, index);
+          const date = new Date(current);
+          const day = date.getDay();
+
+          el.className = `datepicker-cell ${this.cellClass}`;
+          el.dataset.date = current;
+          el.textContent = date.getDate();
+
+          if (current < this.first) {
+            classList.add('prev');
+          } else if (current > this.last) {
+            classList.add('next');
+          }
+          if (this.today === current) {
+            classList.add('today');
+          }
+          if (current < this.minDate || current > this.maxDate || this.disabled.includes(current)) {
+            classList.add('disabled');
+          }
+          if (this.daysOfWeekDisabled.includes(day)) {
+            classList.add('disabled');
+            pushUnique(this.disabled, current);
+          }
+          if (this.daysOfWeekHighlighted.includes(day)) {
+            classList.add('highlighted');
+          }
+          if (this.range) {
+            const [rangeStart, rangeEnd] = this.range;
+            if (current > rangeStart && current < rangeEnd) {
+              classList.add('range');
+            }
+            if (current === rangeStart) {
+              classList.add('range-start');
+            }
+            if (current === rangeEnd) {
+              classList.add('range-end');
+            }
+          }
+          if (this.selected.includes(current)) {
+            classList.add('selected');
+          }
+          if (current === this.focused) {
+            classList.add('focused');
+          }
+
+          if (this.beforeShow) {
+            this.performBeforeHook(el, current, current);
+          }
+        });
+      }
+
+      // Update the view UI by applying the changes of selected and focused items
+      refresh() {
+        const [rangeStart, rangeEnd] = this.range || [];
+        this.grid
+          .querySelectorAll('.range, .range-start, .range-end, .selected, .focused')
+          .forEach((el) => {
+            el.classList.remove('range', 'range-start', 'range-end', 'selected', 'focused');
+          });
+        Array.from(this.grid.children).forEach((el) => {
+          const current = Number(el.dataset.date);
+          const classList = el.classList;
+          if (current > rangeStart && current < rangeEnd) {
+            classList.add('range');
+          }
+          if (current === rangeStart) {
+            classList.add('range-start');
+          }
+          if (current === rangeEnd) {
+            classList.add('range-end');
+          }
+          if (this.selected.includes(current)) {
+            classList.add('selected');
+          }
+          if (current === this.focused) {
+            classList.add('focused');
+          }
+        });
+      }
+
+      // Update the view UI by applying the change of focused item
+      refreshFocus() {
+        const index = Math.round((this.focused - this.start) / 86400000);
+        this.grid.querySelectorAll('.focused').forEach((el) => {
+          el.classList.remove('focused');
+        });
+        this.grid.children[index].classList.add('focused');
+      }
+    }
+
+    function computeMonthRange(range, thisYear) {
+      if (!range || !range[0] || !range[1]) {
+        return;
+      }
+
+      const [[startY, startM], [endY, endM]] = range;
+      if (startY > thisYear || endY < thisYear) {
+        return;
+      }
+      return [
+        startY === thisYear ? startM : -1,
+        endY === thisYear ? endM : 12,
+      ];
+    }
+
+    class MonthsView extends View {
+      constructor(picker) {
+        super(picker, {
+          id: 1,
+          name: 'months',
+          cellClass: 'month',
+        });
+      }
+
+      init(options, onConstruction = true) {
+        if (onConstruction) {
+          this.grid = this.element;
+          this.element.classList.add('months', 'datepicker-grid');
+          this.grid.appendChild(parseHTML(createTagRepeat('span', 12, {'data-month': ix => ix})));
+        }
+        super.init(options);
+      }
+
+      setOptions(options) {
+        if (options.locale) {
+          this.monthNames = options.locale.monthsShort;
+        }
+        if (hasProperty(options, 'minDate')) {
+          if (options.minDate === undefined) {
+            this.minYear = this.minMonth = this.minDate = undefined;
+          } else {
+            const minDateObj = new Date(options.minDate);
+            this.minYear = minDateObj.getFullYear();
+            this.minMonth = minDateObj.getMonth();
+            this.minDate = minDateObj.setDate(1);
+          }
+        }
+        if (hasProperty(options, 'maxDate')) {
+          if (options.maxDate === undefined) {
+            this.maxYear = this.maxMonth = this.maxDate = undefined;
+          } else {
+            const maxDateObj = new Date(options.maxDate);
+            this.maxYear = maxDateObj.getFullYear();
+            this.maxMonth = maxDateObj.getMonth();
+            this.maxDate = dateValue(this.maxYear, this.maxMonth + 1, 0);
+          }
+        }
+        if (options.beforeShowMonth !== undefined) {
+          this.beforeShow = typeof options.beforeShowMonth === 'function'
+            ? options.beforeShowMonth
+            : undefined;
+        }
+      }
+
+      // Update view's settings to reflect the viewDate set on the picker
+      updateFocus() {
+        const viewDate = new Date(this.picker.viewDate);
+        this.year = viewDate.getFullYear();
+        this.focused = viewDate.getMonth();
+      }
+
+      // Update view's settings to reflect the selected dates
+      updateSelection() {
+        const {dates, rangepicker} = this.picker.datepicker;
+        this.selected = dates.reduce((selected, timeValue) => {
+          const date = new Date(timeValue);
+          const year = date.getFullYear();
+          const month = date.getMonth();
+          if (selected[year] === undefined) {
+            selected[year] = [month];
+          } else {
+            pushUnique(selected[year], month);
+          }
+          return selected;
+        }, {});
+        if (rangepicker && rangepicker.dates) {
+          this.range = rangepicker.dates.map(timeValue => {
+            const date = new Date(timeValue);
+            return isNaN(date) ? undefined : [date.getFullYear(), date.getMonth()];
+          });
+        }
+      }
+
+      // Update the entire view UI
+      render() {
+        // refresh disabled months on every render in order to clear the ones added
+        // by beforeShow hook at previous render
+        this.disabled = [];
+
+        this.picker.setViewSwitchLabel(this.year);
+        this.picker.setPrevBtnDisabled(this.year <= this.minYear);
+        this.picker.setNextBtnDisabled(this.year >= this.maxYear);
+
+        const selected = this.selected[this.year] || [];
+        const yrOutOfRange = this.year < this.minYear || this.year > this.maxYear;
+        const isMinYear = this.year === this.minYear;
+        const isMaxYear = this.year === this.maxYear;
+        const range = computeMonthRange(this.range, this.year);
+
+        Array.from(this.grid.children).forEach((el, index) => {
+          const classList = el.classList;
+          const date = dateValue(this.year, index, 1);
+
+          el.className = `datepicker-cell ${this.cellClass}`;
+          if (this.isMinView) {
+            el.dataset.date = date;
+          }
+          // reset text on every render to clear the custom content set
+          // by beforeShow hook at previous render
+          el.textContent = this.monthNames[index];
+
+          if (
+            yrOutOfRange
+            || isMinYear && index < this.minMonth
+            || isMaxYear && index > this.maxMonth
+          ) {
+            classList.add('disabled');
+          }
+          if (range) {
+            const [rangeStart, rangeEnd] = range;
+            if (index > rangeStart && index < rangeEnd) {
+              classList.add('range');
+            }
+            if (index === rangeStart) {
+              classList.add('range-start');
+            }
+            if (index === rangeEnd) {
+              classList.add('range-end');
+            }
+          }
+          if (selected.includes(index)) {
+            classList.add('selected');
+          }
+          if (index === this.focused) {
+            classList.add('focused');
+          }
+
+          if (this.beforeShow) {
+            this.performBeforeHook(el, index, date);
+          }
+        });
+      }
+
+      // Update the view UI by applying the changes of selected and focused items
+      refresh() {
+        const selected = this.selected[this.year] || [];
+        const [rangeStart, rangeEnd] = computeMonthRange(this.range, this.year) || [];
+        this.grid
+          .querySelectorAll('.range, .range-start, .range-end, .selected, .focused')
+          .forEach((el) => {
+            el.classList.remove('range', 'range-start', 'range-end', 'selected', 'focused');
+          });
+        Array.from(this.grid.children).forEach((el, index) => {
+          const classList = el.classList;
+          if (index > rangeStart && index < rangeEnd) {
+            classList.add('range');
+          }
+          if (index === rangeStart) {
+            classList.add('range-start');
+          }
+          if (index === rangeEnd) {
+            classList.add('range-end');
+          }
+          if (selected.includes(index)) {
+            classList.add('selected');
+          }
+          if (index === this.focused) {
+            classList.add('focused');
+          }
+        });
+      }
+
+      // Update the view UI by applying the change of focused item
+      refreshFocus() {
+        this.grid.querySelectorAll('.focused').forEach((el) => {
+          el.classList.remove('focused');
+        });
+        this.grid.children[this.focused].classList.add('focused');
+      }
+    }
+
+    function toTitleCase(word) {
+      return [...word].reduce((str, ch, ix) => str += ix ? ch : ch.toUpperCase(), '');
+    }
+
+    // Class representing the years and decades view elements
+    class YearsView extends View {
+      constructor(picker, config) {
+        super(picker, config);
+      }
+
+      init(options, onConstruction = true) {
+        if (onConstruction) {
+          this.navStep = this.step * 10;
+          this.beforeShowOption = `beforeShow${toTitleCase(this.cellClass)}`;
+          this.grid = this.element;
+          this.element.classList.add(this.name, 'datepicker-grid');
+          this.grid.appendChild(parseHTML(createTagRepeat('span', 12)));
+        }
+        super.init(options);
+      }
+
+      setOptions(options) {
+        if (hasProperty(options, 'minDate')) {
+          if (options.minDate === undefined) {
+            this.minYear = this.minDate = undefined;
+          } else {
+            this.minYear = startOfYearPeriod(options.minDate, this.step);
+            this.minDate = dateValue(this.minYear, 0, 1);
+          }
+        }
+        if (hasProperty(options, 'maxDate')) {
+          if (options.maxDate === undefined) {
+            this.maxYear = this.maxDate = undefined;
+          } else {
+            this.maxYear = startOfYearPeriod(options.maxDate, this.step);
+            this.maxDate = dateValue(this.maxYear, 11, 31);
+          }
+        }
+        if (options[this.beforeShowOption] !== undefined) {
+          const beforeShow = options[this.beforeShowOption];
+          this.beforeShow = typeof beforeShow === 'function' ? beforeShow : undefined;
+        }
+      }
+
+      // Update view's settings to reflect the viewDate set on the picker
+      updateFocus() {
+        const viewDate = new Date(this.picker.viewDate);
+        const first = startOfYearPeriod(viewDate, this.navStep);
+        const last = first + 9 * this.step;
+
+        this.first = first;
+        this.last = last;
+        this.start = first - this.step;
+        this.focused = startOfYearPeriod(viewDate, this.step);
+      }
+
+      // Update view's settings to reflect the selected dates
+      updateSelection() {
+        const {dates, rangepicker} = this.picker.datepicker;
+        this.selected = dates.reduce((years, timeValue) => {
+          return pushUnique(years, startOfYearPeriod(timeValue, this.step));
+        }, []);
+        if (rangepicker && rangepicker.dates) {
+          this.range = rangepicker.dates.map(timeValue => {
+            if (timeValue !== undefined) {
+              return startOfYearPeriod(timeValue, this.step);
+            }
+          });
+        }
+      }
+
+      // Update the entire view UI
+      render() {
+        // refresh disabled years on every render in order to clear the ones added
+        // by beforeShow hook at previous render
+        this.disabled = [];
+
+        this.picker.setViewSwitchLabel(`${this.first}-${this.last}`);
+        this.picker.setPrevBtnDisabled(this.first <= this.minYear);
+        this.picker.setNextBtnDisabled(this.last >= this.maxYear);
+
+        Array.from(this.grid.children).forEach((el, index) => {
+          const classList = el.classList;
+          const current = this.start + (index * this.step);
+          const date = dateValue(current, 0, 1);
+
+          el.className = `datepicker-cell ${this.cellClass}`;
+          if (this.isMinView) {
+            el.dataset.date = date;
+          }
+          el.textContent = el.dataset.year = current;
+
+          if (index === 0) {
+            classList.add('prev');
+          } else if (index === 11) {
+            classList.add('next');
+          }
+          if (current < this.minYear || current > this.maxYear) {
+            classList.add('disabled');
+          }
+          if (this.range) {
+            const [rangeStart, rangeEnd] = this.range;
+            if (current > rangeStart && current < rangeEnd) {
+              classList.add('range');
+            }
+            if (current === rangeStart) {
+              classList.add('range-start');
+            }
+            if (current === rangeEnd) {
+              classList.add('range-end');
+            }
+          }
+          if (this.selected.includes(current)) {
+            classList.add('selected');
+          }
+          if (current === this.focused) {
+            classList.add('focused');
+          }
+
+          if (this.beforeShow) {
+            this.performBeforeHook(el, current, date);
+          }
+        });
+      }
+
+      // Update the view UI by applying the changes of selected and focused items
+      refresh() {
+        const [rangeStart, rangeEnd] = this.range || [];
+        this.grid
+          .querySelectorAll('.range, .range-start, .range-end, .selected, .focused')
+          .forEach((el) => {
+            el.classList.remove('range', 'range-start', 'range-end', 'selected', 'focused');
+          });
+        Array.from(this.grid.children).forEach((el) => {
+          const current = Number(el.textContent);
+          const classList = el.classList;
+          if (current > rangeStart && current < rangeEnd) {
+            classList.add('range');
+          }
+          if (current === rangeStart) {
+            classList.add('range-start');
+          }
+          if (current === rangeEnd) {
+            classList.add('range-end');
+          }
+          if (this.selected.includes(current)) {
+            classList.add('selected');
+          }
+          if (current === this.focused) {
+            classList.add('focused');
+          }
+        });
+      }
+
+      // Update the view UI by applying the change of focused item
+      refreshFocus() {
+        const index = Math.round((this.focused - this.start) / this.step);
+        this.grid.querySelectorAll('.focused').forEach((el) => {
+          el.classList.remove('focused');
+        });
+        this.grid.children[index].classList.add('focused');
+      }
+    }
+
+    function triggerDatepickerEvent(datepicker, type) {
+      const detail = {
+        date: datepicker.getDate(),
+        viewDate: new Date(datepicker.picker.viewDate),
+        viewId: datepicker.picker.currentView.id,
+        datepicker,
+      };
+      datepicker.element.dispatchEvent(new CustomEvent(type, {detail}));
+    }
+
+    // direction: -1 (to previous), 1 (to next)
+    function goToPrevOrNext(datepicker, direction) {
+      const {minDate, maxDate} = datepicker.config;
+      const {currentView, viewDate} = datepicker.picker;
+      let newViewDate;
+      switch (currentView.id) {
+        case 0:
+          newViewDate = addMonths(viewDate, direction);
+          break;
+        case 1:
+          newViewDate = addYears(viewDate, direction);
+          break;
+        default:
+          newViewDate = addYears(viewDate, direction * currentView.navStep);
+      }
+      newViewDate = limitToRange(newViewDate, minDate, maxDate);
+      datepicker.picker.changeFocus(newViewDate).render();
+    }
+
+    function switchView(datepicker) {
+      const viewId = datepicker.picker.currentView.id;
+      if (viewId === datepicker.config.maxView) {
+        return;
+      }
+      datepicker.picker.changeView(viewId + 1).render();
+    }
+
+    function unfocus(datepicker) {
+      if (datepicker.config.updateOnBlur) {
+        datepicker.update({autohide: true});
+      } else {
+        datepicker.refresh('input');
+        datepicker.hide();
+      }
+    }
+
+    function goToSelectedMonthOrYear(datepicker, selection) {
+      const picker = datepicker.picker;
+      const viewDate = new Date(picker.viewDate);
+      const viewId = picker.currentView.id;
+      const newDate = viewId === 1
+        ? addMonths(viewDate, selection - viewDate.getMonth())
+        : addYears(viewDate, selection - viewDate.getFullYear());
+
+      picker.changeFocus(newDate).changeView(viewId - 1).render();
+    }
+
+    function onClickTodayBtn(datepicker) {
+      const picker = datepicker.picker;
+      const currentDate = today();
+      if (datepicker.config.todayBtnMode === 1) {
+        if (datepicker.config.autohide) {
+          datepicker.setDate(currentDate);
+          return;
+        }
+        datepicker.setDate(currentDate, {render: false});
+        picker.update();
+      }
+      if (picker.viewDate !== currentDate) {
+        picker.changeFocus(currentDate);
+      }
+      picker.changeView(0).render();
+    }
+
+    function onClickClearBtn(datepicker) {
+      datepicker.setDate({clear: true});
+    }
+
+    function onClickViewSwitch(datepicker) {
+      switchView(datepicker);
+    }
+
+    function onClickPrevBtn(datepicker) {
+      goToPrevOrNext(datepicker, -1);
+    }
+
+    function onClickNextBtn(datepicker) {
+      goToPrevOrNext(datepicker, 1);
+    }
+
+    // For the picker's main block to delegete the events from `datepicker-cell`s
+    function onClickView(datepicker, ev) {
+      const target = findElementInEventPath(ev, '.datepicker-cell');
+      if (!target || target.classList.contains('disabled')) {
+        return;
+      }
+
+      const {id, isMinView} = datepicker.picker.currentView;
+      if (isMinView) {
+        datepicker.setDate(Number(target.dataset.date));
+      } else if (id === 1) {
+        goToSelectedMonthOrYear(datepicker, Number(target.dataset.month));
+      } else {
+        goToSelectedMonthOrYear(datepicker, Number(target.dataset.year));
+      }
+    }
+
+    function onClickPicker(datepicker) {
+      if (!datepicker.inline && !datepicker.config.disableTouchKeyboard) {
+        datepicker.inputField.focus();
+      }
+    }
+
+    function processPickerOptions(picker, options) {
+      if (options.title !== undefined) {
+        if (options.title) {
+          picker.controls.title.textContent = options.title;
+          showElement(picker.controls.title);
+        } else {
+          picker.controls.title.textContent = '';
+          hideElement(picker.controls.title);
+        }
+      }
+      if (options.prevArrow) {
+        const prevBtn = picker.controls.prevBtn;
+        emptyChildNodes(prevBtn);
+        options.prevArrow.forEach((node) => {
+          prevBtn.appendChild(node.cloneNode(true));
+        });
+      }
+      if (options.nextArrow) {
+        const nextBtn = picker.controls.nextBtn;
+        emptyChildNodes(nextBtn);
+        options.nextArrow.forEach((node) => {
+          nextBtn.appendChild(node.cloneNode(true));
+        });
+      }
+      if (options.locale) {
+        picker.controls.todayBtn.textContent = options.locale.today;
+        picker.controls.clearBtn.textContent = options.locale.clear;
+      }
+      if (options.todayBtn !== undefined) {
+        if (options.todayBtn) {
+          showElement(picker.controls.todayBtn);
+        } else {
+          hideElement(picker.controls.todayBtn);
+        }
+      }
+      if (hasProperty(options, 'minDate') || hasProperty(options, 'maxDate')) {
+        const {minDate, maxDate} = picker.datepicker.config;
+        picker.controls.todayBtn.disabled = !isInRange(today(), minDate, maxDate);
+      }
+      if (options.clearBtn !== undefined) {
+        if (options.clearBtn) {
+          showElement(picker.controls.clearBtn);
+        } else {
+          hideElement(picker.controls.clearBtn);
+        }
+      }
+    }
+
+    // Compute view date to reset, which will be...
+    // - the last item of the selected dates or defaultViewDate if no selection
+    // - limitted to minDate or maxDate if it exceeds the range
+    function computeResetViewDate(datepicker) {
+      const {dates, config} = datepicker;
+      const viewDate = dates.length > 0 ? lastItemOf(dates) : config.defaultViewDate;
+      return limitToRange(viewDate, config.minDate, config.maxDate);
+    }
+
+    // Change current view's view date
+    function setViewDate(picker, newDate) {
+      const oldViewDate = new Date(picker.viewDate);
+      const newViewDate = new Date(newDate);
+      const {id, year, first, last} = picker.currentView;
+      const viewYear = newViewDate.getFullYear();
+
+      picker.viewDate = newDate;
+      if (viewYear !== oldViewDate.getFullYear()) {
+        triggerDatepickerEvent(picker.datepicker, 'changeYear');
+      }
+      if (newViewDate.getMonth() !== oldViewDate.getMonth()) {
+        triggerDatepickerEvent(picker.datepicker, 'changeMonth');
+      }
+
+      // return whether the new date is in different period on time from the one
+      // displayed in the current view
+      // when true, the view needs to be re-rendered on the next UI refresh.
+      switch (id) {
+        case 0:
+          return newDate < first || newDate > last;
+        case 1:
+          return viewYear !== year;
+        default:
+          return viewYear < first || viewYear > last;
+      }
+    }
+
+    function getTextDirection(el) {
+      return window.getComputedStyle(el).direction;
+    }
+
+    // Class representing the picker UI
+    class Picker {
+      constructor(datepicker) {
+        this.datepicker = datepicker;
+
+        const template = pickerTemplate.replace(/%buttonClass%/g, datepicker.config.buttonClass);
+        const element = this.element = parseHTML(template).firstChild;
+        const [header, main, footer] = element.firstChild.children;
+        const title = header.firstElementChild;
+        const [prevBtn, viewSwitch, nextBtn] = header.lastElementChild.children;
+        const [todayBtn, clearBtn] = footer.firstChild.children;
+        const controls = {
+          title,
+          prevBtn,
+          viewSwitch,
+          nextBtn,
+          todayBtn,
+          clearBtn,
+        };
+        this.main = main;
+        this.controls = controls;
+
+        const elementClass = datepicker.inline ? 'inline' : 'dropdown';
+        element.classList.add(`datepicker-${elementClass}`);
+
+        processPickerOptions(this, datepicker.config);
+        this.viewDate = computeResetViewDate(datepicker);
+
+        // set up event listeners
+        registerListeners(datepicker, [
+          [element, 'click', onClickPicker.bind(null, datepicker), {capture: true}],
+          [main, 'click', onClickView.bind(null, datepicker)],
+          [controls.viewSwitch, 'click', onClickViewSwitch.bind(null, datepicker)],
+          [controls.prevBtn, 'click', onClickPrevBtn.bind(null, datepicker)],
+          [controls.nextBtn, 'click', onClickNextBtn.bind(null, datepicker)],
+          [controls.todayBtn, 'click', onClickTodayBtn.bind(null, datepicker)],
+          [controls.clearBtn, 'click', onClickClearBtn.bind(null, datepicker)],
+        ]);
+
+        // set up views
+        this.views = [
+          new DaysView(this),
+          new MonthsView(this),
+          new YearsView(this, {id: 2, name: 'years', cellClass: 'year', step: 1}),
+          new YearsView(this, {id: 3, name: 'decades', cellClass: 'decade', step: 10}),
+        ];
+        this.currentView = this.views[datepicker.config.startView];
+
+        this.currentView.render();
+        this.main.appendChild(this.currentView.element);
+        datepicker.config.container.appendChild(this.element);
+      }
+
+      setOptions(options) {
+        processPickerOptions(this, options);
+        this.views.forEach((view) => {
+          view.init(options, false);
+        });
+        this.currentView.render();
+      }
+
+      detach() {
+        this.datepicker.config.container.removeChild(this.element);
+      }
+
+      show() {
+        if (this.active) {
+          return;
+        }
+        this.element.classList.add('active');
+        this.active = true;
+
+        const datepicker = this.datepicker;
+        if (!datepicker.inline) {
+          // ensure picker's direction matches input's
+          const inputDirection = getTextDirection(datepicker.inputField);
+          if (inputDirection !== getTextDirection(datepicker.config.container)) {
+            this.element.dir = inputDirection;
+          } else if (this.element.dir) {
+            this.element.removeAttribute('dir');
+          }
+
+          this.place();
+          if (datepicker.config.disableTouchKeyboard) {
+            datepicker.inputField.blur();
+          }
+        }
+        triggerDatepickerEvent(datepicker, 'show');
+      }
+
+      hide() {
+        if (!this.active) {
+          return;
+        }
+        this.datepicker.exitEditMode();
+        this.element.classList.remove('active');
+        this.active = false;
+        triggerDatepickerEvent(this.datepicker, 'hide');
+      }
+
+      place() {
+        const {classList, style} = this.element;
+        const {config, inputField} = this.datepicker;
+        const container = config.container;
+        const {
+          width: calendarWidth,
+          height: calendarHeight,
+        } = this.element.getBoundingClientRect();
+        const {
+          left: containerLeft,
+          top: containerTop,
+          width: containerWidth,
+        } = container.getBoundingClientRect();
+        const {
+          left: inputLeft,
+          top: inputTop,
+          width: inputWidth,
+          height: inputHeight
+        } = inputField.getBoundingClientRect();
+        let {x: orientX, y: orientY} = config.orientation;
+        let scrollTop;
+        let left;
+        let top;
+
+        if (container === document.body) {
+          scrollTop = window.scrollY;
+          left = inputLeft + window.scrollX;
+          top = inputTop + scrollTop;
+        } else {
+          scrollTop = container.scrollTop;
+          left = inputLeft - containerLeft;
+          top = inputTop - containerTop + scrollTop;
+        }
+
+        if (orientX === 'auto') {
+          if (left < 0) {
+            // align to the left and move into visible area if input's left edge < window's
+            orientX = 'left';
+            left = 10;
+          } else if (left + calendarWidth > containerWidth) {
+            // align to the right if canlendar's right edge > container's
+            orientX = 'right';
+          } else {
+            orientX = getTextDirection(inputField) === 'rtl' ? 'right' : 'left';
+          }
+        }
+        if (orientX === 'right') {
+          left -= calendarWidth - inputWidth;
+        }
+
+        if (orientY === 'auto') {
+          orientY = top - calendarHeight < scrollTop ? 'bottom' : 'top';
+        }
+        if (orientY === 'top') {
+          top -= calendarHeight;
+        } else {
+          top += inputHeight;
+        }
+
+        classList.remove(
+          'datepicker-orient-top',
+          'datepicker-orient-bottom',
+          'datepicker-orient-right',
+          'datepicker-orient-left'
+        );
+        classList.add(`datepicker-orient-${orientY}`, `datepicker-orient-${orientX}`);
+
+        style.top = top ? `${top}px` : top;
+        style.left = left ? `${left}px` : left;
+      }
+
+      setViewSwitchLabel(labelText) {
+        this.controls.viewSwitch.textContent = labelText;
+      }
+
+      setPrevBtnDisabled(disabled) {
+        this.controls.prevBtn.disabled = disabled;
+      }
+
+      setNextBtnDisabled(disabled) {
+        this.controls.nextBtn.disabled = disabled;
+      }
+
+      changeView(viewId) {
+        const oldView = this.currentView;
+        const newView =  this.views[viewId];
+        if (newView.id !== oldView.id) {
+          this.currentView = newView;
+          this._renderMethod = 'render';
+          triggerDatepickerEvent(this.datepicker, 'changeView');
+          this.main.replaceChild(newView.element, oldView.element);
+        }
+        return this;
+      }
+
+      // Change the focused date (view date)
+      changeFocus(newViewDate) {
+        this._renderMethod = setViewDate(this, newViewDate) ? 'render' : 'refreshFocus';
+        this.views.forEach((view) => {
+          view.updateFocus();
+        });
+        return this;
+      }
+
+      // Apply the change of the selected dates
+      update() {
+        const newViewDate = computeResetViewDate(this.datepicker);
+        this._renderMethod = setViewDate(this, newViewDate) ? 'render' : 'refresh';
+        this.views.forEach((view) => {
+          view.updateFocus();
+          view.updateSelection();
+        });
+        return this;
+      }
+
+      // Refresh the picker UI
+      render(quickRender = true) {
+        const renderMethod = (quickRender && this._renderMethod) || 'render';
+        delete this._renderMethod;
+
+        this.currentView[renderMethod]();
+      }
+    }
+
+    // Find the closest date that doesn't meet the condition for unavailable date
+    // Returns undefined if no available date is found
+    // addFn: function to calculate the next date
+    //   - args: time value, amount
+    // increase: amount to pass to addFn
+    // testFn: function to test the unavailablity of the date
+    //   - args: time value; retun: true if unavailable
+    function findNextAvailableOne(date, addFn, increase, testFn, min, max) {
+      if (!isInRange(date, min, max)) {
+        return;
+      }
+      if (testFn(date)) {
+        const newDate = addFn(date, increase);
+        return findNextAvailableOne(newDate, addFn, increase, testFn, min, max);
+      }
+      return date;
+    }
+
+    // direction: -1 (left/up), 1 (right/down)
+    // vertical: true for up/down, false for left/right
+    function moveByArrowKey(datepicker, ev, direction, vertical) {
+      const picker = datepicker.picker;
+      const currentView = picker.currentView;
+      const step = currentView.step || 1;
+      let viewDate = picker.viewDate;
+      let addFn;
+      let testFn;
+      switch (currentView.id) {
+        case 0:
+          if (vertical) {
+            viewDate = addDays(viewDate, direction * 7);
+          } else if (ev.ctrlKey || ev.metaKey) {
+            viewDate = addYears(viewDate, direction);
+          } else {
+            viewDate = addDays(viewDate, direction);
+          }
+          addFn = addDays;
+          testFn = (date) => currentView.disabled.includes(date);
+          break;
+        case 1:
+          viewDate = addMonths(viewDate, vertical ? direction * 4 : direction);
+          addFn = addMonths;
+          testFn = (date) => {
+            const dt = new Date(date);
+            const {year, disabled} = currentView;
+            return dt.getFullYear() === year && disabled.includes(dt.getMonth());
+          };
+          break;
+        default:
+          viewDate = addYears(viewDate, direction * (vertical ? 4 : 1) * step);
+          addFn = addYears;
+          testFn = date => currentView.disabled.includes(startOfYearPeriod(date, step));
+      }
+      viewDate = findNextAvailableOne(
+        viewDate,
+        addFn,
+        direction < 0 ? -step : step,
+        testFn,
+        currentView.minDate,
+        currentView.maxDate
+      );
+      if (viewDate !== undefined) {
+        picker.changeFocus(viewDate).render();
+      }
+    }
+
+    function onKeydown(datepicker, ev) {
+      if (ev.key === 'Tab') {
+        unfocus(datepicker);
+        return;
+      }
+
+      const picker = datepicker.picker;
+      const {id, isMinView} = picker.currentView;
+      if (!picker.active) {
+        switch (ev.key) {
+          case 'ArrowDown':
+          case 'Escape':
+            picker.show();
+            break;
+          case 'Enter':
+            datepicker.update();
+            break;
+          default:
+            return;
+        }
+      } else if (datepicker.editMode) {
+        switch (ev.key) {
+          case 'Escape':
+            picker.hide();
+            break;
+          case 'Enter':
+            datepicker.exitEditMode({update: true, autohide: datepicker.config.autohide});
+            break;
+          default:
+            return;
+        }
+      } else {
+        switch (ev.key) {
+          case 'Escape':
+            picker.hide();
+            break;
+          case 'ArrowLeft':
+            if (ev.ctrlKey || ev.metaKey) {
+              goToPrevOrNext(datepicker, -1);
+            } else if (ev.shiftKey) {
+              datepicker.enterEditMode();
+              return;
+            } else {
+              moveByArrowKey(datepicker, ev, -1, false);
+            }
+            break;
+          case 'ArrowRight':
+            if (ev.ctrlKey || ev.metaKey) {
+              goToPrevOrNext(datepicker, 1);
+            } else if (ev.shiftKey) {
+              datepicker.enterEditMode();
+              return;
+            } else {
+              moveByArrowKey(datepicker, ev, 1, false);
+            }
+            break;
+          case 'ArrowUp':
+            if (ev.ctrlKey || ev.metaKey) {
+              switchView(datepicker);
+            } else if (ev.shiftKey) {
+              datepicker.enterEditMode();
+              return;
+            } else {
+              moveByArrowKey(datepicker, ev, -1, true);
+            }
+            break;
+          case 'ArrowDown':
+            if (ev.shiftKey && !ev.ctrlKey && !ev.metaKey) {
+              datepicker.enterEditMode();
+              return;
+            }
+            moveByArrowKey(datepicker, ev, 1, true);
+            break;
+          case 'Enter':
+            if (isMinView) {
+              datepicker.setDate(picker.viewDate);
+            } else {
+              picker.changeView(id - 1).render();
+            }
+            break;
+          case 'Backspace':
+          case 'Delete':
+            datepicker.enterEditMode();
+            return;
+          default:
+            if (ev.key.length === 1 && !ev.ctrlKey && !ev.metaKey) {
+              datepicker.enterEditMode();
+            }
+            return;
+        }
+      }
+      ev.preventDefault();
+      ev.stopPropagation();
+    }
+
+    function onFocus(datepicker) {
+      if (datepicker.config.showOnFocus) {
+        datepicker.show();
+      }
+    }
+
+    // for the prevention for entering edit mode while getting focus on click
+    function onMousedown(datepicker, ev) {
+      const el = ev.target;
+      if (datepicker.picker.active || datepicker.config.showOnClick) {
+        el._active = el === document.activeElement;
+        el._clicking = setTimeout(() => {
+          delete el._active;
+          delete el._clicking;
+        }, 2000);
+      }
+    }
+
+    function onClickInput(datepicker, ev) {
+      const el = ev.target;
+      if (!el._clicking) {
+        return;
+      }
+      clearTimeout(el._clicking);
+      delete el._clicking;
+
+      if (el._active) {
+        datepicker.enterEditMode();
+      }
+      delete el._active;
+
+      if (datepicker.config.showOnClick) {
+        datepicker.show();
+      }
+    }
+
+    function onPaste(datepicker, ev) {
+      if (ev.clipboardData.types.includes('text/plain')) {
+        datepicker.enterEditMode();
+      }
+    }
+
+    // for the `document` to delegate the events from outside the picker/input field
+    function onClickOutside(datepicker, ev) {
+      const element = datepicker.element;
+      if (element !== document.activeElement) {
+        return;
+      }
+      const pickerElem = datepicker.picker.element;
+      if (findElementInEventPath(ev, el => el === element || el === pickerElem)) {
+        return;
+      }
+      unfocus(datepicker);
+    }
+
+    function stringifyDates(dates, config) {
+      return dates
+        .map(dt => formatDate(dt, config.format, config.locale))
+        .join(config.dateDelimiter);
+    }
+
+    // parse input dates and create an array of time values for selection
+    // returns undefined if there are no valid dates in inputDates
+    // when origDates (current selection) is passed, the function works to mix
+    // the input dates into the current selection
+    function processInputDates(datepicker, inputDates, clear = false) {
+      const {config, dates: origDates, rangepicker} = datepicker;
+        if (inputDates.length === 0) {
+        // empty input is considered valid unless origiDates is passed
+        return clear ? [] : undefined;
+      }
+
+      const rangeEnd = rangepicker && datepicker === rangepicker.datepickers[1];
+      let newDates = inputDates.reduce((dates, dt) => {
+        let date = parseDate(dt, config.format, config.locale);
+        if (date === undefined) {
+          return dates;
+        }
+        if (config.pickLevel > 0) {
+          // adjust to 1st of the month/Jan 1st of the year
+          // or to the last day of the monh/Dec 31st of the year if the datepicker
+          // is the range-end picker of a rangepicker
+          const dt = new Date(date);
+          if (config.pickLevel === 1) {
+            date = rangeEnd
+              ? dt.setMonth(dt.getMonth() + 1, 0)
+              : dt.setDate(1);
+          } else {
+            date = rangeEnd
+              ? dt.setFullYear(dt.getFullYear() + 1, 0, 0)
+              : dt.setMonth(0, 1);
+          }
+        }
+        if (
+          isInRange(date, config.minDate, config.maxDate)
+          && !dates.includes(date)
+          && !config.datesDisabled.includes(date)
+          && !config.daysOfWeekDisabled.includes(new Date(date).getDay())
+        ) {
+          dates.push(date);
+        }
+        return dates;
+      }, []);
+      if (newDates.length === 0) {
+        return;
+      }
+      if (config.multidate && !clear) {
+        // get the synmetric difference between origDates and newDates
+        newDates = newDates.reduce((dates, date) => {
+          if (!origDates.includes(date)) {
+            dates.push(date);
+          }
+          return dates;
+        }, origDates.filter(date => !newDates.includes(date)));
+      }
+      // do length check always because user can input multiple dates regardless of the mode
+      return config.maxNumberOfDates && newDates.length > config.maxNumberOfDates
+        ? newDates.slice(config.maxNumberOfDates * -1)
+        : newDates;
+    }
+
+    // refresh the UI elements
+    // modes: 1: input only, 2, picker only, 3 both
+    function refreshUI(datepicker, mode = 3, quickRender = true) {
+      const {config, picker, inputField} = datepicker;
+      if (mode & 2) {
+        const newView = picker.active ? config.pickLevel : config.startView;
+        picker.update().changeView(newView).render(quickRender);
+      }
+      if (mode & 1 && inputField) {
+        inputField.value = stringifyDates(datepicker.dates, config);
+      }
+    }
+
+    function setDate(datepicker, inputDates, options) {
+      let {clear, render, autohide} = options;
+      if (render === undefined) {
+        render = true;
+      }
+      if (!render) {
+        autohide = false;
+      } else if (autohide === undefined) {
+        autohide = datepicker.config.autohide;
+      }
+
+      const newDates = processInputDates(datepicker, inputDates, clear);
+      if (!newDates) {
+        return;
+      }
+      if (newDates.toString() !== datepicker.dates.toString()) {
+        datepicker.dates = newDates;
+        refreshUI(datepicker, render ? 3 : 1);
+        triggerDatepickerEvent(datepicker, 'changeDate');
+      } else {
+        refreshUI(datepicker, 1);
+      }
+      if (autohide) {
+        datepicker.hide();
+      }
+    }
+
+    /**
+     * Class representing a date picker
+     */
+    class Datepicker {
+      /**
+       * Create a date picker
+       * @param  {Element} element - element to bind a date picker
+       * @param  {Object} [options] - config options
+       * @param  {DateRangePicker} [rangepicker] - DateRangePicker instance the
+       * date picker belongs to. Use this only when creating date picker as a part
+       * of date range picker
+       */
+      constructor(element, options = {}, rangepicker = undefined) {
+        element.datepicker = this;
+        this.element = element;
+
+        // set up config
+        const config = this.config = Object.assign({
+          buttonClass: (options.buttonClass && String(options.buttonClass)) || 'button',
+          container: document.body,
+          defaultViewDate: today(),
+          maxDate: undefined,
+          minDate: undefined,
+        }, processOptions(defaultOptions, this));
+        this._options = options;
+        Object.assign(config, processOptions(options, this));
+
+        // configure by type
+        const inline = this.inline = element.tagName !== 'INPUT';
+        let inputField;
+        let initialDates;
+
+        if (inline) {
+          config.container = element;
+          initialDates = stringToArray(element.dataset.date, config.dateDelimiter);
+          delete element.dataset.date;
+        } else {
+          const container = options.container ? document.querySelector(options.container) : null;
+          if (container) {
+            config.container = container;
+          }
+          inputField = this.inputField = element;
+          inputField.classList.add('datepicker-input');
+          initialDates = stringToArray(inputField.value, config.dateDelimiter);
+        }
+        if (rangepicker) {
+          // check validiry
+          const index = rangepicker.inputs.indexOf(inputField);
+          const datepickers = rangepicker.datepickers;
+          if (index < 0 || index > 1 || !Array.isArray(datepickers)) {
+            throw Error('Invalid rangepicker object.');
+          }
+          // attach itaelf to the rangepicker here so that processInputDates() can
+          // determine if this is the range-end picker of the rangepicker while
+          // setting inital values when pickLevel > 0
+          datepickers[index] = this;
+          // add getter for rangepicker
+          Object.defineProperty(this, 'rangepicker', {
+            get() {
+              return rangepicker;
+            },
+          });
+        }
+
+        // set initial value
+        this.dates = processInputDates(this, initialDates) || [];
+        if (inputField) {
+          inputField.value = stringifyDates(this.dates, config);
+        }
+
+        const picker = this.picker = new Picker(this);
+
+        if (inline) {
+          this.show();
+        } else {
+          // set up event listeners in other modes
+          const onMousedownDocument = onClickOutside.bind(null, this);
+          const listeners = [
+            [inputField, 'keydown', onKeydown.bind(null, this)],
+            [inputField, 'focus', onFocus.bind(null, this)],
+            [inputField, 'mousedown', onMousedown.bind(null, this)],
+            [inputField, 'click', onClickInput.bind(null, this)],
+            [inputField, 'paste', onPaste.bind(null, this)],
+            [document, 'mousedown', onMousedownDocument],
+            [document, 'touchstart', onMousedownDocument],
+            [window, 'resize', picker.place.bind(picker)]
+          ];
+          registerListeners(this, listeners);
+        }
+      }
+
+      /**
+       * Format Date object or time value in given format and language
+       * @param  {Date|Number} date - date or time value to format
+       * @param  {String|Object} format - format string or object that contains
+       * toDisplay() custom formatter, whose signature is
+       * - args:
+       *   - date: {Date} - Date instance of the date passed to the method
+       *   - format: {Object} - the format object passed to the method
+       *   - locale: {Object} - locale for the language specified by `lang`
+       * - return:
+       *     {String} formatted date
+       * @param  {String} [lang=en] - language code for the locale to use
+       * @return {String} formatted date
+       */
+      static formatDate(date, format, lang) {
+        return formatDate(date, format, lang && locales[lang] || locales.en);
+      }
+
+      /**
+       * Parse date string
+       * @param  {String|Date|Number} dateStr - date string, Date object or time
+       * value to parse
+       * @param  {String|Object} format - format string or object that contains
+       * toValue() custom parser, whose signature is
+       * - args:
+       *   - dateStr: {String|Date|Number} - the dateStr passed to the method
+       *   - format: {Object} - the format object passed to the method
+       *   - locale: {Object} - locale for the language specified by `lang`
+       * - return:
+       *     {Date|Number} parsed date or its time value
+       * @param  {String} [lang=en] - language code for the locale to use
+       * @return {Number} time value of parsed date
+       */
+      static parseDate(dateStr, format, lang) {
+        return parseDate(dateStr, format, lang && locales[lang] || locales.en);
+      }
+
+      /**
+       * @type {Object} - Installed locales in `[languageCode]: localeObject` format
+       * en`:_English (US)_ is pre-installed.
+       */
+      static get locales() {
+        return locales;
+      }
+
+      /**
+       * @type {Boolean} - Whether the picker element is shown. `true` whne shown
+       */
+      get active() {
+        return !!(this.picker && this.picker.active);
+      }
+
+      /**
+       * @type {HTMLDivElement} - DOM object of picker element
+       */
+      get pickerElement() {
+        return this.picker ? this.picker.element : undefined;
+      }
+
+      /**
+       * Set new values to the config options
+       * @param {Object} options - config options to update
+       */
+      setOptions(options) {
+        const picker = this.picker;
+        const newOptions = processOptions(options, this);
+        Object.assign(this._options, options);
+        Object.assign(this.config, newOptions);
+        picker.setOptions(newOptions);
+
+        refreshUI(this, 3);
+      }
+
+      /**
+       * Show the picker element
+       */
+      show() {
+        if (this.inputField && this.inputField.disabled) {
+          return;
+        }
+        this.picker.show();
+      }
+
+      /**
+       * Hide the picker element
+       * Not available on inline picker
+       */
+      hide() {
+        if (this.inline) {
+          return;
+        }
+        this.picker.hide();
+        this.picker.update().changeView(this.config.startView).render();
+      }
+
+      /**
+       * Destroy the Datepicker instance
+       * @return {Detepicker} - the instance destroyed
+       */
+      destroy() {
+        this.hide();
+        unregisterListeners(this);
+        this.picker.detach();
+        if (!this.inline) {
+          this.inputField.classList.remove('datepicker-input');
+        }
+        delete this.element.datepicker;
+        return this;
+      }
+
+      /**
+       * Get the selected date(s)
+       *
+       * The method returns a Date object of selected date by default, and returns
+       * an array of selected dates in multidate mode. If format string is passed,
+       * it returns date string(s) formatted in given format.
+       *
+       * @param  {String} [format] - Format string to stringify the date(s)
+       * @return {Date|String|Date[]|String[]} - selected date(s), or if none is
+       * selected, empty array in multidate mode and untitled in sigledate mode
+       */
+      getDate(format = undefined) {
+        const callback = format
+          ? date => formatDate(date, format, this.config.locale)
+          : date => new Date(date);
+
+        if (this.config.multidate) {
+          return this.dates.map(callback);
+        }
+        if (this.dates.length > 0) {
+          return callback(this.dates[0]);
+        }
+      }
+
+      /**
+       * Set selected date(s)
+       *
+       * In multidate mode, you can pass multiple dates as a series of arguments
+       * or an array. (Since each date is parsed individually, the type of the
+       * dates doesn't have to be the same.)
+       * The given dates are used to toggle the select status of each date. The
+       * number of selected dates is kept from exceeding the length set to
+       * maxNumberOfDates.
+       *
+       * With clear: true option, the method can be used to clear the selection
+       * and to replace the selection instead of toggling in multidate mode.
+       * If the option is passed with no date arguments or an empty dates array,
+       * it works as "clear" (clear the selection then set nothing), and if the
+       * option is passed with new dates to select, it works as "replace" (clear
+       * the selection then set the given dates)
+       *
+       * When render: false option is used, the method omits re-rendering the
+       * picker element. In this case, you need to call refresh() method later in
+       * order for the picker element to reflect the changes. The input field is
+       * refreshed always regardless of this option.
+       *
+       * When invalid (unparsable, repeated, disabled or out-of-range) dates are
+       * passed, the method ignores them and applies only valid ones. In the case
+       * that all the given dates are invalid, which is distinguished from passing
+       * no dates, the method considers it as an error and leaves the selection
+       * untouched.
+       *
+       * @param {...(Date|Number|String)|Array} [dates] - Date strings, Date
+       * objects, time values or mix of those for new selection
+       * @param {Object} [options] - function options
+       * - clear: {boolean} - Whether to clear the existing selection
+       *     defualt: false
+       * - render: {boolean} - Whether to re-render the picker element
+       *     default: true
+       * - autohide: {boolean} - Whether to hide the picker element after re-render
+       *     Ignored when used with render: false
+       *     default: config.autohide
+       */
+      setDate(...args) {
+        const dates = [...args];
+        const opts = {};
+        const lastArg = lastItemOf(args);
+        if (
+          typeof lastArg === 'object'
+          && !Array.isArray(lastArg)
+          && !(lastArg instanceof Date)
+          && lastArg
+        ) {
+          Object.assign(opts, dates.pop());
+        }
+
+        const inputDates = Array.isArray(dates[0]) ? dates[0] : dates;
+        setDate(this, inputDates, opts);
+      }
+
+      /**
+       * Update the selected date(s) with input field's value
+       * Not available on inline picker
+       *
+       * The input field will be refreshed with properly formatted date string.
+       *
+       * @param  {Object} [options] - function options
+       * - autohide: {boolean} - whether to hide the picker element after refresh
+       *     default: false
+       */
+      update(options = undefined) {
+        if (this.inline) {
+          return;
+        }
+
+        const opts = {clear: true, autohide: !!(options && options.autohide)};
+        const inputDates = stringToArray(this.inputField.value, this.config.dateDelimiter);
+        setDate(this, inputDates, opts);
+      }
+
+      /**
+       * Refresh the picker element and the associated input field
+       * @param {String} [target] - target item when refreshing one item only
+       * 'picker' or 'input'
+       * @param {Boolean} [forceRender] - whether to re-render the picker element
+       * regardless of its state instead of optimized refresh
+       */
+      refresh(target = undefined, forceRender = false) {
+        if (target && typeof target !== 'string') {
+          forceRender = target;
+          target = undefined;
+        }
+
+        let mode;
+        if (target === 'picker') {
+          mode = 2;
+        } else if (target === 'input') {
+          mode = 1;
+        } else {
+          mode = 3;
+        }
+        refreshUI(this, mode, !forceRender);
+      }
+
+      /**
+       * Enter edit mode
+       * Not available on inline picker or when the picker element is hidden
+       */
+      enterEditMode() {
+        if (this.inline || !this.picker.active || this.editMode) {
+          return;
+        }
+        this.editMode = true;
+        this.inputField.classList.add('in-edit');
+      }
+
+      /**
+       * Exit from edit mode
+       * Not available on inline picker
+       * @param  {Object} [options] - function options
+       * - update: {boolean} - whether to call update() after exiting
+       *     If false, input field is revert to the existing selection
+       *     default: false
+       */
+      exitEditMode(options = undefined) {
+        if (this.inline || !this.editMode) {
+          return;
+        }
+        const opts = Object.assign({update: false}, options);
+        delete this.editMode;
+        this.inputField.classList.remove('in-edit');
+        if (opts.update) {
+          this.update(opts);
+        }
+      }
+    }
+
     /*
      * Licensed to the Apache Software Foundation (ASF) under one or more
      * contributor license agreements.  See the NOTICE file distributed with
@@ -8144,7 +10670,7 @@
             const i18n = this.i18n;
             i18n.titleFormat = "MM y"; // todo i18n
             i18n.format = this.pattern;
-            Datepicker__default['default'].locales[locale] = i18n;
+            Datepicker.locales[locale] = i18n;
             const options = {
                 buttonClass: "btn",
                 orientation: "bottom top auto",
@@ -8155,7 +10681,7 @@
                 // todo readonly
                 // todo show week numbers
             };
-            const datepicker = new Datepicker__default['default'](field, options);
+            const datepicker = new Datepicker(field, options);
             // XXX these listeners are needed as long as we have a solution for:
             // XXX https://github.com/mymth/vanillajs-datepicker/issues/13
             // XXX the 2nd point is missing the "normal" change event on the input element
diff --git a/tobago-theme/tobago-theme-standard/npm/package-lock.json b/tobago-theme/tobago-theme-standard/npm/package-lock.json
index 442cb56..8510725 100644
--- a/tobago-theme/tobago-theme-standard/npm/package-lock.json
+++ b/tobago-theme/tobago-theme-standard/npm/package-lock.json
@@ -704,31 +704,6 @@
       "integrity": "sha512-cPqjjzuFWNK3BSKLm0abspP0sp/IGOli4p5I5fKFAzdS8fvjdOwDCfZqAaIiXd9lPkOWi3SUUfZof3hEb7J/uw==",
       "dev": true
     },
-    "@rollup/plugin-node-resolve": {
-      "version": "11.1.0",
-      "resolved": "https://registry.npmjs.org/@rollup/plugin-node-resolve/-/plugin-node-resolve-11.1.0.tgz",
-      "integrity": "sha512-ouBBppRdWJKCllDXGzJ7ZIkYbaq+5TmyP0smt1vdJCFfoZhLi31vhpmjLhyo8lreHf4RoeSNllaWrvSqHpHRog==",
-      "dev": true,
-      "requires": {
-        "@rollup/pluginutils": "^3.1.0",
-        "@types/resolve": "1.17.1",
-        "builtin-modules": "^3.1.0",
-        "deepmerge": "^4.2.2",
-        "is-module": "^1.0.0",
-        "resolve": "^1.19.0"
-      },
-      "dependencies": {
-        "@types/resolve": {
-          "version": "1.17.1",
-          "resolved": "https://registry.npmjs.org/@types/resolve/-/resolve-1.17.1.tgz",
-          "integrity": "sha512-yy7HuzQhj0dhGpD8RLXSZWEkLsV9ibvxvi6EiJ3bkqLAO1RGo0WbkWQiwpRlSFymTJRz0d3k5LM3kkx8ArDbLw==",
-          "dev": true,
-          "requires": {
-            "@types/node": "*"
-          }
-        }
-      }
-    },
     "@rollup/plugin-replace": {
       "version": "2.3.4",
       "resolved": "https://registry.npmjs.org/@rollup/plugin-replace/-/plugin-replace-2.3.4.tgz",
@@ -894,6 +869,15 @@
       "integrity": "sha512-6gOkRe7OIioWAXfnO/2lFiv+SJichKVSys1mSsgyrYHSEjk8Ctv4tSR/Odvnu+HWlH2C8j53dahU03XmQdd5fA==",
       "dev": true
     },
+    "@types/resolve": {
+      "version": "0.0.8",
+      "resolved": "https://registry.npmjs.org/@types/resolve/-/resolve-0.0.8.tgz",
+      "integrity": "sha512-auApPaJf3NPfe18hSoJkp8EbZzer2ISk7o8mCC3M9he/a04+gbMF97NkpD2S8riMGvm4BMRI59/SZQSaLTKpsQ==",
+      "dev": true,
+      "requires": {
+        "@types/node": "*"
+      }
+    },
     "@types/stack-utils": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/@types/stack-utils/-/stack-utils-2.0.0.tgz",
@@ -2209,6 +2193,12 @@
       "integrity": "sha512-39nnKffWz8xN1BU/2c79n9nB9HDzo0niYUqx6xyqUnyoAnQyyWpOTdZEeiCch8BBu515t4wp9ZmgVfVhn9EBpw==",
       "dev": true
     },
+    "estree-walker": {
+      "version": "0.6.1",
+      "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-0.6.1.tgz",
+      "integrity": "sha512-SqmZANLWS0mnatqbSfRP5g8OXZC12Fgg1IwNtLsyHDzJizORW4khDfjPqJZsemPWBB2uqykUah5YpQ6epsqC/w==",
+      "dev": true
+    },
     "esutils": {
       "version": "2.0.3",
       "resolved": "https://registry.npmjs.org/esutils/-/esutils-2.0.3.tgz",
@@ -5240,6 +5230,28 @@
         }
       }
     },
+    "rollup-plugin-node-resolve": {
+      "version": "5.2.0",
+      "resolved": "https://registry.npmjs.org/rollup-plugin-node-resolve/-/rollup-plugin-node-resolve-5.2.0.tgz",
+      "integrity": "sha512-jUlyaDXts7TW2CqQ4GaO5VJ4PwwaV8VUGA7+km3n6k6xtOEacf61u0VXwN80phY/evMcaS+9eIeJ9MOyDxt5Zw==",
+      "dev": true,
+      "requires": {
+        "@types/resolve": "0.0.8",
+        "builtin-modules": "^3.1.0",
+        "is-module": "^1.0.0",
+        "resolve": "^1.11.1",
+        "rollup-pluginutils": "^2.8.1"
+      }
+    },
+    "rollup-pluginutils": {
+      "version": "2.8.2",
+      "resolved": "https://registry.npmjs.org/rollup-pluginutils/-/rollup-pluginutils-2.8.2.tgz",
+      "integrity": "sha512-EEp9NhnUkwY8aif6bxgovPHMoMoNr2FulJziTndpt5H9RdwC47GSGuII9XxpSdzVGM0GWrNPHV6ie1LTNJPaLQ==",
+      "dev": true,
+      "requires": {
+        "estree-walker": "^0.6.1"
+      }
+    },
     "rsvp": {
       "version": "4.8.5",
       "resolved": "https://registry.npmjs.org/rsvp/-/rsvp-4.8.5.tgz",
@@ -6371,9 +6383,9 @@
       }
     },
     "vanillajs-datepicker": {
-      "version": "1.1.1",
-      "resolved": "https://registry.npmjs.org/vanillajs-datepicker/-/vanillajs-datepicker-1.1.1.tgz",
-      "integrity": "sha512-rvws7iIGWUCM5XaH9dSmyNGQtt+Jl3IlohBjy/hjDs1Vnet+tQRhx6Dr7wq4f9CiN07sHC+663VAyGgObGmOcg=="
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/vanillajs-datepicker/-/vanillajs-datepicker-1.1.2.tgz",
+      "integrity": "sha512-ATnGZRznbAT1ghuXEIderk3/+ylPXfm/ESiobG7R7HuS62/fCFFEPS1Q55NCDj0w8EBq/RzIiPUU6NpxW2VE3A=="
     },
     "verror": {
       "version": "1.10.0",
diff --git a/tobago-theme/tobago-theme-standard/npm/package.json b/tobago-theme/tobago-theme-standard/npm/package.json
index 7e9d07e..074952d 100644
--- a/tobago-theme/tobago-theme-standard/npm/package.json
+++ b/tobago-theme/tobago-theme-standard/npm/package.json
@@ -72,7 +72,7 @@
     "npm-run-all": "^4.1.5",
     "postcss-cli": "^7.1.2",
     "rollup": "^2.37.1",
-    "@rollup/plugin-node-resolve": "^11.1.0",
+    "rollup-plugin-node-resolve": "^5.2.0",
     "@rollup/plugin-replace": "^2.3.4",
     "sass": "^1.29.0",
     "ts-jest": "^26.4.4",
diff --git a/tobago-theme/tobago-theme-standard/npm/rollup.config.js b/tobago-theme/tobago-theme-standard/npm/rollup.config.js
index b8407bd..649e44e 100644
--- a/tobago-theme/tobago-theme-standard/npm/rollup.config.js
+++ b/tobago-theme/tobago-theme-standard/npm/rollup.config.js
@@ -15,7 +15,10 @@
  * limitations under the License.
  */
 
-import resolve from "@rollup/plugin-node-resolve"
+import resolve from "rollup-plugin-node-resolve"
+// fixme: "@rollup/plugin-node-resolve" is the new version of "rollup-plugin-node-resolve", but doesn't work with
+// the vaillajs-datepicker
+// import resolve from "@rollup/plugin-node-resolve"
 import replace from '@rollup/plugin-replace';
 
 export default {