javascript - AngularJS - Stack trace ignoring source map

Question

I've written an AngularJS app but it's proving a bit of a nightmare to debug. I'm using Grunt + uglify to concatenate and minify my application code. It also creates a source map alongside the minified JS file.

The source map seems to work properly when there is a JS error in the file, but outside of the AngularJS application. e.g. If I write console.log('a.b'); at the top of one of the files, the error logged in the Chrome debugger displays line + file info for the original file, not the minified one.

The problem occurs when there is a problem with code that Angular runs itself (e.g. in Controller code). I get a nice stack trace from Angular, but it only details the minified file not the original.

Is there anything I can do to get Angular to acknowledge the source map?

Example error below:

TypeError: Cannot call method 'getElement' of undefined
at Object.addMapControls (http://my-site/wp-content/plugins/my-maps/assets/js/app.min.js:1:2848)
at Object.g [as init] (http://my-site/wp-content/plugins/my-maps/assets/js/app.min.js:1:344)
at new a (http://my-site/wp-content/plugins/my-maps/assets/js/app.min.js:1:591)
at d (http://ajax.googleapis.com/ajax/libs/angularjs/1.2.0-rc.2/angular.min.js:29:495)
at Object.instantiate (http://ajax.googleapis.com/ajax/libs/angularjs/1.2.0-rc.2/angular.min.js:30:123)

Answer 1

Larrifax's answer is good but there is an improved version of the function documented in the same issue report:

.config(function($provide) {

  // Fix sourcemaps
  // @url https://github.com/angular/angular.js/issues/5217#issuecomment-50993513
  $provide.decorator('$exceptionHandler', function($delegate) {
    return function(exception, cause) {
      $delegate(exception, cause);
      setTimeout(function() {
        throw exception;
      });
    };
  });
})

This will generate two stack traces, as Andrew Magee noted: one formatted by Angular, then a second one formatted by the browser. The second trace will apply sourcemaps. It's probably not a great idea to disable the duplicates, because you may have other Angular modules that also do work with exceptions that could be called after this via the delegation.