Mixins for Underscore.js

underscore_js_mixins.js

// blog post: http://blog.slashpoundbang.com/post/4047203519/mixins-for-underscore-js

_.mixin({
  // @param array obj An array of two-element arrays, where the first element is
  //   the key and the second element is the value.
  // @returns object A JavaScript object declaring key-value pairs.
  toObj: function (obj) {
    return _.reduce(obj, function (memo, array) {
      memo[array[0]] = array[1];
      return memo;
    }, {});
  },
  // @param object obj A JavaScript object declaring key-value pairs.
  // @param function iterator The sorting function.
  // @param context context A context (optional).
  // @returns object obj The JavaScript object with its key-value pairs sorted
  //   by value according to the sorting function.
  sortObj: function (obj, iterator, context) {
    return _.toObj(_.pluck(_.map(obj, function(value, index, list) {
      return {
        value : [index, value],
        criteria : iterator.call(context, value, index, list)
      };
    }).sort(function(left, right) {
      var a = left.criteria, b = right.criteria;
      return a < b ? -1 : a > b ? 1 : 0;
    }), 'value'));
  }
});