Function zoneify

packages/zone.js/lib/common/promise.ts:614–626

(fn: Function)

    api.patchThen = patchThen;

    function zoneify(fn: Function) {
      return function (self: any, args: any[]) {
        let resultPromise = fn.apply(self, args);
        if (resultPromise instanceof ZoneAwarePromise) {
          return resultPromise;
        }
        let ctor = resultPromise.constructor;
        if (!ctor[symbolThenPatched]) {
          patchThen(ctor);
        }
        return resultPromise;
      };
    }

    if (NativePromise) {
      patchThen(NativePromise);