这个前端代码太鬼畜了，完全看不懂了~有大神说一下吗？

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这是一个创建于 2918 天前的主题，其中的信息可能已经有所发展或是发生改变。

代码如下： (f =>(x => f(y => x(x)(y)))(x => f(y => x(x)(y))) )(get => node => Array.from(node.childNodes) .filter(node => node.nodeType === Node.ELEMENT_NODE).reduce((depth, node) => Math.max(depth, get(node) + 1), 1) )(document.documentElement)

微博链接： http://weibo.com/1074886493/EodjO45ln?type=comment#_rnd1482937548088

15 条回复 • 2017-01-02 21:54:14 +08:00

hxsf

2016-12-28 23:53:46 +08:00 via iPhone

手机阅读。没啥格式化工具。

目测是遍历 dom 树返回最大深度

关键字
箭头函数立即执行函数

exoticknight

2016-12-29 00:05:47 +08:00

去看看 Y Combinator ，然后应该就懂了……

xcatliu

2016-12-29 00:37:13 +08:00

不知道把代码写成这样有什么意义

alexsunxl

2016-12-29 01:13:07 +08:00

作用就跟一楼说那样了，获得 dom 树最大深度
其实执行一下就知道了，一般这种就是从右往左边看
附图

lijsh

2016-12-29 02:29:13 +08:00

美化一下：
(f =>
(x => f(y => x(x)(y)))
(x => f(y => x(x)(y)))
)
(get =>
node =>
Array.from(node.childNodes)
.filter(node => node.nodeType === Node.ELEMENT_NODE)
.reduce((depth, node) => Math.max(depth, get(node) + 1), 1)
)
(document.documentElement)

(f =>
(x => f(y => x(x)(y)))
(x => f(y => x(x)(y)))
)
这种形式是 Y Combinator ，作用是让匿名函数递归自身。

node =>
Array.from(node.childNodes)
.filter(node => node.nodeType === Node.ELEMENT_NODE)
.reduce((depth, node) => Math.max(depth, get(node) + 1), 1)

这里就是找 node 的后代元素嵌套深度的，后面把 document.documentElement 传进来。

lijsh

2016-12-29 02:30:00 +08:00

本想美化一下，没想到排版还是瞎眼…

yidinghe

2016-12-29 09:23:02 +08:00

试下 markdown

```
function(abc) {
alert("Hello!");
}
```

apoclast

2016-12-29 13:10:05 +08:00

注意力从前端挪走几年了. 现在浏览器支持的 javascript 引擎是什么版本? 什么样的浏览器能支持这种函数式的 js 语法?

se77en

2016-12-29 14:01:04 +08:00

@apoclast 主要的浏览器现在都支持了，而且 ES6 规范里规定了 tail call optimization

kopp123

2016-12-29 17:00:16 +08:00

这还算鬼畜。这才叫鬼畜
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