jQuery: global exception handler

Question

Possible Duplicate:
JavaScript Exception Handling

I have a web application where 100% of the javascript code executes as jQuery event handlers (I guess most jQuery apps are like this).

The question is how can I define a global exception handler. That is, if a function that is called when any exception that happens within any jQuery event handler goes uncaught (whether it is onload, click, a succesfull ajax call, an ajax error, whatever). My function would receive the error info (exception, stacktrace, whatever).

Clarification: I don't mean globally catching in ajax problems generated by the server or network, but globally catching problems that are due to (presumably) bugs in our code.

score 15 · Answer 1 · answered Jan 17 '13 at 08:20

15

You can use window.onerror : https://developer.mozilla.org/en-US/docs/DOM/window.onerror

window.onerror = function errorHandler(msg, url, line) {

  console.log(arguments);

  // Just let default handler run.
  return false;
}

answered Jan 17 '13 at 08:20

Romain Meresse

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2

this almost never works. :) `Note that some/many error events do not trigger window.onerror, you have to listen for them specifically` they said. – mayankcpdixit Jun 15 '15 at 14:13
@mayankcpdixit [Works for me](https://jsfiddle.net/5mpL7u0p/). Can you cite an example of something that doesn't get caught? – doug65536 Jul 20 '16 at 07:52
Modern style [works too](https://jsfiddle.net/5mpL7u0p/1/). – doug65536 Jul 20 '16 at 07:54
2

Well for example: If you are using Angular, errors wont pass through `window.onerror`. You have to handle them using factory. `window.onerror` is not triggered when the console directly generates an error. – mayankcpdixit Jul 24 '16 at 11:14
jQuery.Deferred exception won't be caught by this – jsaddwater May 05 '17 at 12:58
Good solution. One remark: there should be a semicolon after closing curly bracket, because this is an assignment statement. – Dawid Ohia Feb 04 '21 at 08:48

Minko Gechev · Accepted Answer · 2013-01-17T08:39:48.060

I guess this can be achieved using concepts from the Aspect-oriented programming.

We can simply create a wrapper of jQuery.event.dispatch which will handle the errors:

(function () {
    var temp = jQuery.event.handle;
    jQuery.event.handle = function () {
       try {
          temp.apply(this, arguments);
       } catch (e) {
          console.log('Error while dispatching the event.');
       }
    }
}());
$(document).click(function () {
    throw 'Some error...';
});

Using this approach you must be very careful because of changes in the internal interface

Note the example above works for jQuery v1.6.3, in jQuery 1.7.1 jQuery.event.dispatch instead of jQuery.event.handle.

jQuery: global exception handler

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