[GitHub] [couchdb-nano] kozlovzxc opened a new issue #263: Fields param is missing for changesreader.get

[GitBox <gi...@apache.org>]

kozlovzxc opened a new issue #263:
URL: https://github.com/apache/couchdb-nano/issues/263


   ## Expected Behavior
   
   [The CouchDB documentation](https://docs.couchdb.org/en/stable/api/database/changes.html#selector) describes that it is possible to provide _selector for `_chages` handler
   ```
   POST /recipes/_changes?filter=_selector HTTP/1.1
   Content-Type: application/json
   Host: localhost:5984
   
   {
       "selector": { "_id": { "$regex": "^_design/" } }
   }
   ```
   
   [The documentation also describes](https://docs.couchdb.org/en/stable/api/database/find.html#filtering-fields) that selector can contain a list of specified fields to filter.
   
   ```
   {
       "selector": { "Actor_name": "Robert De Niro" },
       "fields": ["Actor_name", "Movie_year", "_id", "_rev"]
   }
   ```
   
   ## Current Behavior
   
   Right now it is only possible to provide the `selector` parameter, but not the `fields` parameter. [Link](https://github.com/apache/couchdb-nano/blob/c84d0a43b13edc888a2a339f7fb057ad66d3d3fe/lib/changesreader.js#L168)
   ```
             if (self.selector) {
               req.qs.filter = '_selector'
               req.body.selector = self.selector
             }
   ```
   
   ## Possible Solution
   
   Locally I've fixed it just by adding another parameter. It can be something like this:
   ```
             if (self.selector || self.fields) {
               req.qs.filter = '_selector'
               req.body.selector = self.selector
               req.body.fields = self.fields
             }
   ```
   
   It also may worth adding another custom `body` param similar to `qs`, which adds additional body params. 
   ```
             Object.assign(req.qs, opts.qs)
             // New
             Object.assign(req.body, opts.body)
   ```
   
   ## Steps to Reproduce (for bugs)
   
   It should be straightforward to reproduce, but I can add exact steps if needed.
   
   ## Context
   
   I was trying to fetch few fields from https://replicate.npmjs.com, but I didn't need all extra fields as versions, because it noticeably slows the script down and increases network consumption.
   
   [More context](https://github.com/npm/registry/blob/master/docs/REPLICATE-API.md)
   
   ## Your Environment
   * Version used:   `"nano": "^9.0.3",`
   


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