Chaining asynchronous JavaScript calls with Angular JS

callChain.js

angularModule.
  factory(
    'callChain',
    [
      function() {
        return function () {
          var cs;
          cs = [];
          this.add = function (call) {
            cs.push(call);
          };
          this.execute = function () {
            var wrap, i;
            wrap = function (call, callback) {
              return function () {
                call(callback);
              };
            };
            for (i = cs.length - 1; i > -1; i--) {
              cs[i] = wrap(cs[i], i < cs.length - 1 ? cs[i + 1] : null);
            }
            cs[0]();
          };
        };
      }
    ]
  );