手写实现call方法
实现步骤：
1、将函数设为对象的属性
2、执行该函数
3、删除该函数
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| Function.prototype.call = function (context) {
var context = context || window;
context.fn = this;
var args = [];
for(var i = 1, len = arguments.length; i < len; i++) {
args.push('arguments[' + i + ']');
}
var result = eval('context.fn(' + args +')');
delete context.fn
return result;
}
var value = 2;
var obj = {
value: 1
}
function bar(name, age) {
console.log(this.value);
return {
value: this.value,
name: name,
age: age
}
}
bar.call(null);
console.log(bar.call(obj, 'kevin', 18));
|
