Decorator for async function in angular

async.function.decorator.js

import decoratorHelper from 'decorator.helper';

// Current decorator allow async function to be used in angular
// without adding unnecessary digest calls
const ngAync = function () {
  return function (target, key, descriptor) {

    const fn = descriptor.value;
    descriptor.value = function () {
      const result = fn.apply(this, arguments);
      
      // To work our decorator we need injector, but we
      // managed to access $injectro only from angular.run
      // function
      const $injector = decoratorHelper.injector;

      $injector.invoke(($rootScope, $q) => {
        'ngInject';

        // Force new digest
        $q.when(result)
          .then(() => $rootScope.$applyAsync());
      });
    };
  };
};

export default ngAync;

decorator.helper.js

class DecoratorHelper {
  get injector() {
    return this.injectorInstance;
  }
  set injector(injector) {
    this.injectorInstance = injector;
  }
}

const helper = new DecoratorHelper();

export default helper;

decorator.run.js

// Load module to register run handler, where we store 
// $injector
import angularModule from 'currentAngularModule';

import decoratorHelper from 'decorator.helper';

angularModule.run($injector => {
  'ngInject';

  // Store injector in helper, it will be used by
  // decorators to invisible integration of decorators
  // with Angular
  decoratorHelper.injector = $injector;
});