[jira] [Commented] (CB-2303) Add event for script errors

["Jesse MacFadyen (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CB-2303?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13628396#comment-13628396 ] 

Jesse MacFadyen commented on CB-2303:
-------------------------------------

Instead of mapping to a new cordova document level event, why not actually just call onerror of window?

instead of: 
  javascript:cordova.fireDocumentEvent(...)
this: 
  javascript:window.onerror(msg,fileName,lineNumber)

presumably the developer could already have written a handler ...
window.onerror = function(msg){ ... };
This would allow the same js code to run on multiple devices.

Does this descend into recursive hell?


                
> Add event for script errors
> ---------------------------
>
>                 Key: CB-2303
>                 URL: https://issues.apache.org/jira/browse/CB-2303
>             Project: Apache Cordova
>          Issue Type: New Feature
>          Components: Android
>            Reporter: Jonathan Prince
>            Assignee: Joe Bowser
>
> Android webview does not support window.onerror for catching unexpected javascript errors. This makes cross platform error logging and analysis very difficult (especially on released software).
> A new event could easily be added to enable developers to track javascript errors.
> e.g. in CordovaChromeClient.java change the onConsoleMessage override from 
> {code:title=CordovaChromeClient.java - Current method|borderStyle=solid}
>     @TargetApi(8)
>     @Override
>     public boolean onConsoleMessage(ConsoleMessage consoleMessage)
>     {
>         if (consoleMessage.message() != null)
>             LOG.d(TAG, consoleMessage.message());
>         return super.onConsoleMessage(consoleMessage);
>     }
> {code}
> All this currently does is re-log messages. Changing the method to the below also triggers a scripterror event for errors (this is just proof of concept code but works correctly). Developers can easily map this event to call a standard error handler.
> {code:title=CordovaChromeClient.java - Suggested method|borderStyle=solid}
>     @TargetApi(8)
>     @Override
>     public boolean onConsoleMessage(ConsoleMessage consoleMessage)
>     {
>         if (consoleMessage.message() != null)
>         {
>             if (consoleMessage.messageLevel().name() == "ERROR")
>             {
>             	String errorUrl = "javascript:cordova.fireDocumentEvent('scripterror', {msg: \"" + consoleMessage.message() + "\", line: " + consoleMessage.lineNumber() + ", url: \"" + consoleMessage.sourceId() + "\"});";
>                 this.appView.loadUrl(errorUrl);
>             	LOG.e(TAG, consoleMessage.message() + " line " + consoleMessage.lineNumber() + " in " + consoleMessage.sourceId());
>             }
>             else
>             {
>                 LOG.d(TAG, consoleMessage.message());
>             }
>         }
>         return super.onConsoleMessage(consoleMessage);
>     }
> {code}
> The only quirk I have found with this approach is that javascript calls to console.error also trigger the scripterror event. This actually seems logical but developers should be aware of it.
> Otherwise; unexpected script errors and thrown errors trigger the event and handled errors (in try...catch blocks) don't.

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