这些JavaScript编程黑科技，高逼格代码，让你惊叹不已

 Javascript是编程逼格一门很牛的语言，我可能学了假的黑科JavaScript，哈哈！技高

1、代码单行写一个评级组件

"★★★★★☆☆☆☆☆".slice(5 - rate,让惊 10 - rate);定义一个变量rate是1到5的值，然后执行上面代码，编程逼格看图

才发现插件什么的黑科都弱爆了

2、如何装逼用代码骂别人SB

(!(~+[])+{ })[--[~+""][+[]]*[~+[]] + ~~!+[]]+({ }+[])[[~!+[]]*~+[]]

了解为什么请移步：一行能装逼的技高JavaScript代码

3、如何用代码优雅的代码证明自己NB

这个牛逼了

console.log(([][[]]+[])[+!![]]+([]+{ })[!+[]+!![]])

4、JavaScript 错误处理的让惊方式的正确姿势

，舅服你

try { something} catch (e) { window.location.href ="//stackoverflow.com/search?编程逼格q=[js]+" +e.message;}

5、从一行代码里面学点JavaScript

[].forEach.call($$("*"),黑科function(a){ a.style.outline="1px solid #"+(~~(Math.random()*(1<<24))).toString(16)})

翻译成正常语言就是这样的

Array.prototype.forEach.call(document.querySelectorAll(*),dom => dom.style.outline = `1px solid #${ parseInt(Math.random() * Math.pow(2,24)).toString(16)}`)

接下来在浏览器控制看看：something magic happens

6、论如何优雅的技高取随机字符串

Math.random().toString(16).substring(2)Math.random().toString(36).substring(2)

7、(10)["toString"]() === "10"

解析请移步：js奇淫技巧1

8、代码匿名函数自执行

这么多写法你选择哪一种？让惊我选择死亡。

9、另外一种undefined

从来不需要声明一个变量的值是undefined，因为JavaScript会自动把一个未赋值的变量置为undefined。源码下载所有如果你在代码里这么写，会被鄙视的

var data = undefined;

但是如果你就是强迫症发作，一定要再声明一个暂时没有值的变量的时候赋上一个undefined。那你可以考虑这么做：

var data = void 0; // undefined

void在JavaScript中是一个操作符，对传入的操作不执行并且返回undefined。void后面可以跟()来用，例如void(0)，看起来是不是很熟悉？没错，在HTML里阻止带href的默认点击操作时，都喜欢把href写成javascript:void(0)，实际上也是依靠void操作不执行的意思。

当然，除了出于装逼的原因外，实际用途上不太赞成使用void，因为void的出现是为了兼容早起ECMAScript标准中没有undefined属性。void 0的写法让代码晦涩难懂。

10、云服务器论如何优雅的取整

var a = ~~2.33var b= 2.33 | 0var c= 2.33 >> 0

11、如何优雅的实现金钱格式化：1234567890 --> 1,234,567,890

用正则魔法实现：

非正则的优雅实现：

12、这个我服，还有这个你很机智

我服

while (1) { alert(牛逼你把我关了啊)}

你很机智，好一个障眼法

清除缓存： <a href="javascript:alert(清除成功);">清除缓存</a>

13、逗号运算符

var a = 0;var b = ( a++, 99 );console.log(a); // 1console.log(b); // 99

14、论如何最佳的让两个整数交换数值

常规办法：

var a=1,b=2;a += b;b = a - b;a -= b;

缺点也很明显，整型数据溢出，对于32位字符最大表示数字是2147483647，如果是2147483645和2147483646交换就失败了。

黑科技办法：

a ^= b;b ^= a;a ^= b;

哈哈，看不懂的童鞋建议去补习一下C语言的位操作，我就不去复习了，以前学嵌入式时候学的位操作都忘了

15、实现标准JSON的深拷贝

var a = { a: 1,b: { c: 1, d: 2 }}var b=JSON.parse(JSON.stringify(a))

不考虑IE的情况下，标准JSON格式的对象蛮实用，不过对于undefined和function的会忽略掉。

16、不用Number、parseInt和parseFloat和方法把"1"字符串转换成数字

哈哈，亿华云计算不准用强制类型转换，那么就想到了强大了隐式转换

var a =1 +a

17、如何装逼的写出"hello world!"

滚动条很长哦

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居然能运行，牛逼的隐式转换

18、parseInt(0.0000008) === 8

19、++[[]][+[]]+[+[]] == 10

强大的隐式转换，23333

20、0.1 + 0.2 == 0.3

0.1 +0.2 == 0.3 竟然是不成立的。。。。所以这就是为什么数据库存储对于货币的最小单位都是分。

简单说，0.1和0.2的二进制浮点表示都不是精确的，所以相加后不是0.3，接近（不等于）

0.30000000000000004。

所以，比较数字时，应该有个宽容值。ES6中这个宽容值被预定义了：

Number.EPSILON

。

21、最短的代码实现数组去重

[...new Set([1, "1", 2, 1, 1, 3])]

前不久面试阿里就问了这道题，哈哈，所以也写上一下

22、用最短的代码实现一个长度为m(6)且值都n(8)的数组

Array(6).fill(8)

这个够短了吧，好像是当初哪里看到的一个面试题，就自己想到了ES6的一些API

23、短路表达式

条件判断

var a = b && 1// 相当于if (b) { a = 1} else { a = b}var a = b || 1// 相当于if (b) { a = b} else { a = 1}

24、JavaScript版迷宫

逃出迷宫，2333

25、取出一个数组中的最大值和最小值

var numbers = [5, 458 , 120 , -215 , 228 , 400 , 122205, -85411];var maxInNumbers = Math.max.apply(Math, numbers);var minInNumbers = Math.min.apply(Math, numbers);

26、将argruments对象转换成数组

var argArray = Array.prototype.slice.call(arguments);或者ES6：var argArray = Array.from(arguments)

27、javascript高逼格之Function构造函数

很多JavaScript教程都告诉我们，不要直接用内置对象的构造函数来创建基本变量，例如var arr = new Array(2); 的写法就应该用var arr = [1, 2];的写法来取代。

但是，Function构造函数（注意是大写的Function）有点特别。Function构造函数接受的参数中，第一个是要传入的参数名，第二个是函数内的代码（用字符串来表示）。

var f = new Function(a, alert(a));f(jawil); // 将会弹出窗口显示jawil

这种方式可以根据传入字符串内容来创建一个函数 是不是高大上？！

28、从一个数组中找到一个数，O(n)的算法，找不到就返回 null。

正常的版本:

function find (x, y) { for ( let i = 0; i < x.length; i++ ) { if ( x[i] == y ) return i;} return null;}let arr = [0,1,2,3,4,5]console.log(find(arr, 2))console.log(find(arr, 8))

结果到了函数式成了下面这个样子（好像上面的那些代码在下面若影若现，不过又有点不太一样，为了消掉if语言，让其看上去更像一个表达式，动用了 ? 号表达式）：

//函数式的版本const find = ( f => f(f) ) ( f =>(next => (x, y, i = 0) =>( i >= x.length) ? null :( x[i] == y ) ? i :next(x, y, i+1))((...args) =>(f(f))(...args)))let arr = [0,1,2,3,4,5]console.log(find(arr, 2))console.log(find(arr, 8))