angular.merge polyfill for angular < 1.4.0

angularMergePolyfill.js

    if (!angular.merge) {
      angular.merge = (function mergePollyfill() {
        function setHashKey(obj, h) {
          if (h) {
            obj.$$hashKey = h;
          } else {
            delete obj.$$hashKey;
          }
        }

        function baseExtend(dst, objs, deep) {
          var h = dst.$$hashKey;

          for (var i = 0, ii = objs.length; i < ii; ++i) {
            var obj = objs[i];
            if (!angular.isObject(obj) && !angular.isFunction(obj)) continue;
            var keys = Object.keys(obj);
            for (var j = 0, jj = keys.length; j < jj; j++) {
              var key = keys[j];
              var src = obj[key];

              if (deep && angular.isObject(src)) {
                if (angular.isDate(src)) {
                  dst[key] = new Date(src.valueOf());
                } else {
                  if (!angular.isObject(dst[key])) dst[key] = angular.isArray(src) ? [] : {};
                  baseExtend(dst[key], [src], true);
                }
              } else {
                dst[key] = src;
              }
            }
          }

          setHashKey(dst, h);
          return dst;
        }

        return function merge(dst) {
          return baseExtend(dst, [].slice.call(arguments, 1), true);
        }
      })();
    }