javascript - 通用功能？

Question

我想找出这个问题的答案:

Without using Javascript's bind function, implement the magic function so that:

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?';

我想我需要使用电话或申请，但我只是不知道，如果有人能指出我正确的方向或提供一些文献，我将不胜感激。

Answer 1

你可以使用闭包，和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?');

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你也可以看看Polyfill for bind MDN 上的函数