Underscore mixin with common iterator functions adapted to work with objects and maintain key/val pairs.

_.objMapFunctions.js

_.mixin({
  // ### _.objMap
  // _.map for objects, keeps key/value associations
  objMap: function (input, mapper, context) {
    return _.reduce(input, function (obj, v, k) {
             obj[k] = mapper.call(context, v, k, input);
             return obj;
           }, {}, context);
  },
  // ### _.objFilter
  // _.filter for objects, keeps key/value associations
  // but only includes the properties that pass test().
  objFilter: function (input, test, context) {
    return _.reduce(input, function (obj, v, k) {
             if (test.call(context, v, k, input)) {
               obj[k] = v;
             }
             return obj;
           }, {}, context);
  },
  // ### _.objReject
  //
  // _.reject for objects, keeps key/value associations
  // but does not include the properties that pass test().
  objReject: function (input, test, context) {
    return _.reduce(input, function (obj, v, k) {
             if (!test.call(context, v, k, input)) {
               obj[k] = v;
             }
             return obj;
           }, {}, context);
  }
});

See jashkenas/underscore#220

I added filter and reject, as per this issue: jashkenas/underscore#359.

And also because I needed it for the Drupal Backbone module.

Nice

Very useful, thank you

+1 +1 +1
Can't even begin to describe how often I use these!!!

thanks for this

Thanks dude.

Hey, I'd like to package this. Can you add a license?

Hey, just following up. Would you mind adding a license to this gist? Underscore uses MIT, or you could put it in the public domain. Thanks!