这个前端代码太鬼畜了，完全看不懂了~有大神说一下吗？

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

去看看 Y Combinator ，然后应该就懂了……

不知道把代码写成这样有什么意义

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

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。

本想美化一下，没想到排版还是瞎眼…

试下 markdown

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

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?

@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

这还算鬼畜。这才叫鬼畜
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@kopp123 居然真的能执行哈哈哈哈哈哈哈

@kopp123 可怕，试了下真可以

jsfuck

@kopp123 卧槽，神马原理。。

箭头函数没有原函数语法清晰 我觉得