JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.0/angular.min.js"></script>

JavaScript

angular.module('myApp', [])
	.run(function (MyService) {
    MyService.method();
  })
	.service('MyService', function ($timeout) {
    this.key = 'value';
    this.method = function () {
      console.log(this) // service
      
      $timeout(function () {
        window.alert(this); // window because callback is called from the window
      }, 0);
    }
  });
  
angular.bootstrap(document.querySelector('#app'), ['myApp']);