Constant

作用

顾名思义，就是定义常量 Module.constant(key, value) is used to inject a constant value

如何使用

    var app = angular.module('app', []);
    app.value('myValue', 'weee');

    // use it in a service
    myService.$inejct = ['myValue'];

    function myService(myValue){
     return {
       whatsMyThing: function() {
          return myValue; //weee
       }
      };
    }

    // use it in a controller

    app.controller('someController', someController);
    someController.$inject = ['myValue'];

    function someController(myValue) {
        var vm = this;
        vm.foo = myvalue;
    }

参考

https://docs.angularjs.org/api/auto/service/$provide http://stackoverflow.com/questions/13015523/angular-js-is-value-the-proper-way-to-set-app-wide-constant-and-how-to-retri