通用函數？

Question

我試圖找出這個問題的答案：

不使用JavaScript的綁定功能，實現了神奇的功能，使：

var add = function(a, b) { return a + b; } 
var addTo = add.magic(2); 

var say = function(something) { return something; } 
var welcome = say.magic('Hi, how are you?'); 

addTo(5) == 7; 
welcome() == 'Hi, how are you?'; 

我想我需要使用電話或適用，但我只是不知道，如果有人能指出我在正確的方向或提供一些文獻，將不勝感激。

Answer 1

您可以使用封閉，並apply function

Function.prototype.magic = function(){ 
 
    var self = this; 
 
    var args = Array.from(arguments); 
 
    
 
    return function(){ 
 
    return self.apply(null, args.concat(Array.from(arguments))); 
 
    } 
 
} 
 

 

 
var add = function(a, b) { return a + b; } 
 
var addTo = add.magic(2); 
 

 
var say = function(something) { return something; } 
 
var welcome = say.magic('Hi, how are you?'); 
 

 
console.log(addTo(5) == 7); 
 
console.log(welcome() == 'Hi, how are you?');

---

你也可以看看 Polyfill for bind功能上MDN

Answer 2

請參見下面的代碼：

Object.prototype.magic = function (message) { 
     alert(message); 
    } 
    var add = function (a, b) { return a + b; } 
    var addTo = add.magic(2); 

    var say = function (something) { return something; } 
    var welcome = say.magic('Hi, how are you?'); 

    addTo(5) == 7; 
    welcome() == 'Hi, how are you?';