【转】这些JavaScript编程黑科技，装逼指南，高逼格代码，让你惊叹不已
Javascript是一门很吊的语言，我可能学了假的JavaScript，哈哈，大家还有什么推荐的
本文秉承着：你看不懂是你SB，我写的代码就要牛逼。
1、单行写一个评级组件
"★★★★★☆☆☆☆☆".slice(5 - rate, 10 - rate);定义一个变量rate是1到5的值，然后执行上面代码，看图
才发现插件什么的都弱爆了
2、如何装逼用代码骂别人SB
(!(~+[])+{})[--[~+""][+[]][~+[]] +!+[]]+({}+[])[[~!+[]]~+[]]
3、如何用代码优雅的证明自己NB
这个牛逼了
console.log(([][[]]+[])[+!![]]+([]+{})[!+[]+!![]])
4、JavaScript 错误处理的方式的正确姿势
😂😂😂，舅服你
try { something}catch (e) {
window.location.href ="http://stackoverflow.com/search?q=[js]+" + e.message;
}
5、从一行代码里面学点JavaScript
[].forEach.call($$("*"),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
具体分析请参见这篇文章：从一行代码里面学点JavaScript
6、论如何优雅的取随机字符串
Math.random().toString(16).substring(2)// 13位
Math.random().toString(36).substring(2)// 11位
7、(10)"toString"=== "10"
8、匿名函数自执行
这么多写法你选择哪一种？我选择死亡。
(function() {}() );
(function() {} )();
[function() {}() ];
~function() {}();
!function() {}();
+function() {}();
-function() {}();
deletefunction() {}();
typeoffunction() {}();
voidfunction() {}();
newfunction() {}();
newfunction() {};
var f =function() {}();
1,function() {}();
1 ^function() {}();
1 >function() {}();// ...
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。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：```javascript
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、论如何优雅的取整
var a = ~~2.33
var b=2.33 |0
var 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：
var test1 ='1234567890'
var format = test1.replace(/\B(?=(\d{3})+(?!\d))/g,',')
console.log(format)// 1,234,567,890
非正则的优雅实现：
functionformatCash(str) {
return str.split('').reverse().reduce((prev, next, index) => {return ((index %3) ? next : (next +',')) + prev })}
console.log(formatCash('1234567890'))// 1,234,567,890
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：清除缓存
13、逗号运算符
var a =0;
var b = ( a++,99 );
console.log(a);// 1
console.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，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
[...newSet([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:
functionfind (x, y) {for (let i =0; i < x.length; i++ ) {if ( x[i] == y )return i; }returnnull;}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))
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