An AngularJS Decorator to format negative numbers with the currency filter.

negativeNumberConfigPhase.js

angular.module('app')
  .config(function ($provide) {
    $provide.decorator('$locale', function ($delegate) {
      if ($delegate.id == 'en-us') {
        $delegate.NUMBER_FORMATS.PATTERNS[1].negPre = '-\u00A4';
        $delegate.NUMBER_FORMATS.PATTERNS[1].negSuf = '';
      }
      return $delegate;
    });
  });