javascript之__proto__

发表于 | 更新于 | 评论数： | 阅读次数：

proto作用

用法

今天在看chalk源码时，发现这么一段话：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
function build(_styles) {
	var builder = function () {
		return applyStyle.apply(builder, arguments);
	};

	builder._styles = _styles;
	builder.enabled = this.enabled;
	// __proto__ is used because we must return a function, but there is
	// no way to create a function with a different prototype.
	/* eslint-disable no-proto */
	builder.__proto__ = proto;

	return builder;
}

用proto是因为要返回一个方法，而且要带上一个不同的原型。

实验

我们用以下方法来做个测试：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
var proto1 = defineProps(function chalk1() {}, {

	'ss':  {
				get: function () {
				return  "ssssss";
			}
		}
});

console.log(proto1.ss);
function build(_styles) {
	var builder = function () {

	};

	// __proto__ is used because we must return a function, but there is
	// no way to create a function with a different prototype.
	/* eslint-disable no-proto */
	builder.__proto__ = proto1;
	return builder;
}

var _b = build();
console.log(_b.ss);

输出:

1
2
ssssss
ssssss

参考资料：
create function in javascript with custom prototype
Is it possible to create a function with another prototype than Function.prototype?

欢迎关注我的公众号:沉迷Spring
显示 Gitment 评论
0%