JavaScript 编程黑科技

装逼用代码骂别人

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

用代码优雅的证明自己

• ([][[]]+[])[+!![]]+([]+{})[!+[]+!![]]

优雅的实现金钱格式化

• var price = '1234567890';
• var format = price.replace(/\B(?=(\d{3})+(?!\d))/g, ',');

最佳的让两个整数交换数值

• var a = 1, b = 2;
• a ^= b;
• b ^= a;
• a ^= b;

函数节流

• function throttle(method, context) {

• if (!method.tId) { 
  

•     method.call(context); 
  

•     method.tId = 1; 
  

•     setTimeout(() => method.tId = 0, 100); 
  

• } 
  

• }

不用 Number、parseInt 和 parseFloat 方法把字符串转换成数字

• var a = 1;

装逼的 "hello world!"

• ([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]]([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]())[+[]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]]([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]()([][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]]([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]()(([]+{})[+[]])[+[]]+(!+[]+!![]+!![]+!![]+!![]+!![]+!![]+[])+(!+[]+!![]+!![]+!![]+!![]+!![]+!![]+[]))+([]+{})[+!![]]+(!![]+[])[+!![]]+(![]+[])[!+[]+!![]]+([][[]]+[])[!+[]+!![]]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]]([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]()([][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]]([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]()(([]+{})[+[]])[+[]]+(!+[]+!![]+[])+(+!![]+[]))

最短的代码实现数组去重

• ①ES6实现
• function unique(arr){
• return [...new Set(arr)];
• }
• ②ES5实现
• function unique(arr) {

• return arr.filter(function(ele, index, array) {
  

•     return array.indexOf(ele) === index
  

• })
  

• }
• ③ES3实现
• function unique(arr) {

• var obj = {},
  

•     array = []
  

• for (var i = 0, len = arr.length; i < len; i++) {
  

•     var key = arr[i] + typeof arr[i]
  

•     if (!obj[key]) {
  

•         obj[key] = true
  

•         array.push(arr[i])
  

•     }
  

• }
  

• return array
  

• }
• ③正则实现
• function unique(arr) {

• return arr.sort().join(",,").
  

• replace(/(,|^)([^,]+)(,,\2)+(,|$)/g, "$1$2$4").
  

• replace(/,,+/g, ",").
  

• replace(/,$/, "").
  

• split(",")
  

• }

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);

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);

将 argruments 对象转换成数组

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

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;
  

• }
• // 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)))
  

去掉字符串左右两边的空格

• function trim(str) {

• return str.replace(/(^\s*)|(\s*$)/g, "")
  

• }