Javascript | 將對象函數作為參數傳遞給另一個對象

Question

我目前正在用JavaScript構建GUI，並且希望能夠將一個對象函數作為參數傳遞給另一個對象，下面的代碼演示了該問題和預期的輸出。

var Window = function(){
    this.close = function(){
        console.log(this)
    }
}


var Button = function(func){
    this.func = func;
    this.press = function(){
        this.func();
    }
}

var win = new Window();
var button = new Button(win.close);

button.press();
//Output: Button object
//Expected output: Window object

Answer 1

你應該綁定的功能，你想要的對象this引用。 檢查此MDN參考以了解如何使用Function#bind

 var Window = function(){ this.close = function(){ console.log(this) } this.close = this.close.bind(this) } var Button = function(func){ this.func = func; this.press = function(){ this.func(); } } var win = new Window(); var button = new Button(win.close); button.press(); 

Answer 2

var Button = function(func){
    //this.func = func; this is not required.
    this.press = function(){
       func(); //just call func
    }
}

Answer 3

 var Window = function(){ var w = {}; w.close = function(){ console.log(w); } return w; } var Button = function(func){ var b = {press: func}; return b; } var win = new Window(); var button = new Button(win.close); button.press(); 

Answer 4

您可以保留這樣的參考：

 var Window = function(){ var context= this; this.close = function(){ console.log(context) //output: Object { close: Window/this.close() } } } var Button = function(func){ this.func = func; this.press = function(){ this.func(); } } var win = new Window(); var button = new Button(win.close); button.press(); 

Answer 5

您需要將外部“ this”作為另一個變量傳遞給press（），如下所示。 我將“ this”分配給“ self”，並在press（）中引用了它。 這是我對您的代碼所做的唯一更改。

var Window = function(){
  this.close = function(){
    console.log(this)
  }
}


var Button = function(func){
   let self = this;      // this is the change I made
   this.func = func;
   this.press = function(){
     self.func();        // this is the change I made
  }
}

var win = new Window();
var button = new Button(win.close);

button.press();