_.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);
  }
});