javascript遍历对象数组

Question

我正在Angular应用程序中工作，并在控制器内工作，我需要迭代对象数组。这是控制器以及参与这种情况下，代码：

myapp.controller('LoginController', ['$scope', function(scope) { 
    // Users for test 
    this.users = [ 
     { 
      name: 'admin', 
      password: 'admin', 
      role: 'ADMIN' 
     }, 
     { 
      name: 'employee', 
      password: '12345', 
      role: 'EMPLOYEE' 
     } 
    ]; 
    console.dir(this.users); // Prints an array of objects correctly 

    // called when user submits 
    scope.login = function() { 
     console.log('login(). User: '); 
     console.dir(scope.user); // Prints the object with user's input (also correct) 

     var found = false; 

     for(let u of this.users) { 
      console.log('Comparing with:'); 
      console.dir(u); 

      if(u.name == scope.user.name && u.password == scope.user.password) { 
       console.log('Found!'); 
       found = true; 

       // do something else... 
      } 
     } 

     if(!found) { // show error message... } 
    } 
}]); 

的问题是，当我提交登录表单（来电scope.login()）我在控制台收到一条错误消息：

TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined 
    at m.scope.login (loginController.js:44) 
    ... 

loginController.js:44对应for(let u of this.users) {一行。我通过网络进行搜索（W3学校，MDN和这个网站），但解决方案并没有为我工作。我已经尝试以下解决方案：

• for(var u of this.users)
• var u; for(u in this.users)
• for(var i = 0; i < this.users.lenght; i++)：这改变了错误消息Cannot read property 'length' of undefined

我觉得它的东西简单，但我cant't图搞清楚它是什么（我对Javascript不熟练，对不起）。任何人都可以帮我解决这个问题吗？

在此先感谢您的答案。

Answer 1

范围登录功能内改变，所以变量this是不一样的面前，因为它是该函数内。

scope.login = function() {之前，你可以这样写：

var _this = this;

然后用_this.users.forEach(function(user) {

或for (var i = 0; i < _this.users.length; i++)

Answer 2

您scope.login = function() {}内的this环境的变化，因为它是一个对象的方法，this是scope参考。试试这个：

myapp.controller('LoginController', ['$scope', function(scope) { 
    var that = this; // reference to the correct this context 
    // Users for test 
    this.users = [ 
     { 
      name: 'admin', 
      password: 'admin', 
      role: 'ADMIN' 
     }, 
     { 
      name: 'employee', 
      password: '12345', 
      role: 'EMPLOYEE' 
     } 
    ]; 
    console.dir(this.users); // Prints an array of objects correctly 

    // called when user submits 
    scope.login = function() { 
     console.log('login(). User: '); 
     console.dir(scope.user); // Prints the object with user's input (also correct) 

     var found = false; 
     for(let u of that.users) { // use the correct context here 
      console.log('Comparing with:'); 
      console.dir(u); 

      if(u.name == scope.user.name && u.password == scope.user.password) { 
       console.log('Found!'); 
       found = true; 

       // do something else... 
      } 
     } 

     if(!found) { // show error message... } 
    } 
}]);