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// ~符号用在JavaScript中有按位取反的作用，~~即是取反两次，而位运算的操作值要求是整数，其结果也是整数，所以经过位运算的都会自动变成整数，可以巧妙的去掉小数部分，类似于parseInt，比如：

let a = 1.23;
let b = -1.23;

console.log(~~a); // 1
console.log(~~b); // -1

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let CHARS = 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz0123456789-_.~!*()'; // except \'
function decToRadixN(radixChars, numLen) {
  let result = [];
  let radix = radixChars.length;
  return function cacl(dec) {
    result.unshift(dec % radix);
    if (dec >= radix) {
      dec = Math.floor(dec / radix);
      return cacl(dec, radix);
    }

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function getThirdResoure() {
  var resp = null;
  var tags = document.querySelectorAll('iframe[src],frame[src],script[src],link[rel=stylesheet],object[data],embed[src]');
  for(var i = 0; i < tags.length; i++){
    var tag = tags[i];
    var a = document.createElement('a');
    a.href = tag.src||tag.href||tag.data;
    if(a.hostname != location.hostname){
      resp = resp || [];
      resp.push({name: tag.localName, href: a.href});

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function toUnicodeSequence(str) {
  for(var i = str.length; i--;) {
    str = str.slice(0, i) + '\\u'
        + ('000' + str.charCodeAt(i).toString(16)).slice(-4)
        + str.slice(i + 1);
  }
  return str;
}

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let func = (function f(a) {
  console.log(a);
  return f;
})('hello world');

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Array.prototype.unique = function() { //查找索引 indexOf
  var ret = []
  for (var i = 0; i < this.length; i++) {
    if (ret.indexOf(this[i]) == -1) {
      ret.push(this[i])
    }
  }
  return ret;
}
Array.prototype.unique = function() { //借用对象

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// reduce方法
let arr = [1, 2, 3, 4, 5, 6];
let reduceResult = arr.reduce((x, y) => {
  return x + y
}, 123);
console.log(reduceResult);

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    // 返回字符串的实际长度, 一个汉字算2个长度   
    String.prototype.strlen = function () {  
        return this.replace(/[^\x00-\xff]/g, "**").length;  
    }  

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let fs = require('fs');
let crypto = require('crypto');

let path = '/Users/lushijie/Pictures/day1.jpg';
let start = new Date().getTime();
let md5sum = crypto.createHash('md5');
let stream = fs.createReadStream(path);
stream.on('data', function(chunk) {
    md5sum.update(chunk);
});

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    // http://lib.baomitu.com/crypto-js/3.1.9-1/crypto-js.js
    function encrypt(content, key) {
        var encryptResult = CryptoJS.AES.encrypt(
          content,
          key,
          {
            //iv: key,
            mode: CryptoJS.mode.ECB,
            padding: CryptoJS.pad.Pkcs7
          }