function extend(dst, obj) {
        for (var i in obj) {
            if (obj.hasOwnProperty(i)) {
                dst[i] = obj[i]
            }
        }
    }

const {pwd,...data} = obj //去除密码这一项

剩下的data就是去除了pwd的数据

const pureObject = Object.create(null);
console.log(pureObject); //=> {}
console.log(pureObject.constructor); //=> undefined
console.log(pureObject.toString); //=> undefined
console.log(pureObject.hasOwnProperty); //=> undefined

function Chunk(arr = [], size = 1) {
  return arr.length
    ? arr.reduce(
        (t, v) => (t[t.length - 1].length === size ? t.push([v]) : t[t.length - 1].push(v), t),
        [[]],
      )
    : [];
}

const arr = [1, 2, 3, 4, 5];
Chunk(arr, 2); // [[1, 2], [3, 4], [5]]

function Difference(arr = [], oarr = []) {
    return arr.reduce((t, v) => (!oarr.includes(v) && t.push(v), t), []);
}


const arr1 = [1, 2, 3, 4, 5];
const arr2 = [2, 3, 6]
Difference(arr1, arr2); // [1, 4, 5]

function Flat(arr = []) {
    return arr.reduce((t, v) => t.concat(Array.isArray(v) ? Flat(v) : v), [])
}


const arr = [0, 1, [2, 3], [4, 5, [6, 7]], [8, [9, 10, [11, 12]]]];
Flat(arr); // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

function Uniq(arr = []) {
    return arr.reduce((t, v) => t.includes(v) ? t : [...t, v], []);
}


const arr = [2, 1, 0, 3, 2, 1, 2];
Uniq(arr); // [2, 1, 0, 3]

let arr = [1,2,3,3];
let unique = [...new Set(arr)];

products.reduce((obj, product) => {
                    obj[product.id] = product
                    return obj
                }, {})

 var a={length:2,0:'first',1:'second'};
 Array.prototype.slice.call(a);//  ["first", "second"]
  
 var a={length:2};
 Array.prototype.slice.call(a);//  [undefined, undefined]

const csvFileLine = '1997,John Doe,US,john@doe.com,New York';
const { 2: country, 4: state } = csvFileLine.split(',');

country			// US
state			// New Yourk

  let arr = [1, 2, 3, 3, true, true, [2, 2], [2, 2], [1, 2, [3, 4]], [1, 2, [3, 4]], {name: 'aaa'}, {father: 'fff'}, {name: 'aaa'}];

  function unique(arr) {
    var hash = {};
    return arr.filter(function (element) {
      var key = JSON.stringify(element);
      return hash.hasOwnProperty(key) ? false : (hash[key] = true)
    });
  }

  console.log(unique(arr))

function isJson(str) {
    const start = str.match(/^\s*(\[|\{)/);
    const end = {'[': /]\s*$/, '{': /}\s*$/};
    return start && end[start[1]].test(str);
}

没有g全局标志,那么start[0]保存的是完整的匹配,start[1]保存的是第一个括号里捕获的字串

function isObject (obj) {
  return obj !== null && typeof obj === 'object'
}

function isFunction(source) {
     return '[object Function]' === Object.prototype.toString.call(source);
 };

const isFirefox = typeof navigator !== 'undefined' && navigator.userAgent.toLowerCase().indexOf('firefox') > -1;

function isPromise (val) {
  return val && typeof val.then === 'function'
}

  function test() {
    return new Promise((resolve, reject) => {
      resolve("asdasd")
    })
  }
  
  
  console.log(test.then) //undefined  (很明显就存在then)

function isAsyncFunction(fn) {
  return Object.prototype.toString.call(fn) === "[object AsyncFunction]"
}

根据
fn.constructor.name === "AsyncFunction"
 
来判断

function isElement(value) {
  return (
    typeof HTMLElement === 'object' ? value instanceof HTMLElement : //DOM2
      value && typeof value === "object" && value !== null && value.nodeType === 1 && typeof value.nodeName==="string"
  );
}

var arr = 'abcdaabc';

var info = arr
    .split('')
    .reduce((p, k) => (p[k]++ || (p[k] = 1), p), {});

console.log(info); //{ a: 3, b: 2, c: 2, d: 1 }

const array1 = [1, 2, 3, 4];
const reducer = (accumulator, currentValue) => accumulator + currentValue;

// 1 + 2 + 3 + 4
console.log(array1.reduce(reducer));
// expected output: 10

// 5 + 1 + 2 + 3 + 4
console.log(array1.reduce(reducer, 5));
// expected output: 15

...action.products.reduce((obj,product)=>{
                obj[product.id] = product
                return obj
              },{})

var a = 10, b = 20;

function CommaTest(){
return a++, b++, 10;
}

var c = CommaTest();

alert(a); // 返回11
alert(b); // 返回21
alert(c); // 返回10

var a = 20;
var b = ++a,10;
alert(b);   //不能运行

var a = 20;
var b = (++a,10);
alert(b);

var a = 20;
(var b = ++a),10;
alert(b);

for (i = 0; i < 10; i++, j++)
{
k = i + j;
}

Number({}) ==> NaN        // 这里表示转换的过程，这个等式并不成立
Number.isNaN(Number({}))  // true

{} == "[object Object]"   // true
{} == 0                   // false 看起来好像显然，但实际是 NaN != 0

Math.min(255, Math.max(0, this.touch.left + deltaX))

const anagrams = str => {

  if (str.length <= 2) return str.length === 2 ? [str, str[1] + str[0]] : [str];

  return str.split('').reduce((acc, letter, i) =>

    acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)), []);

};

// anagrams('abc') -> ['abc','acb','bac','bca','cab','cba']

    const TIMEOUT = 100
    let result = "result" //result可以是任意类型的数据
    let getProducts = (cb, timeout) => setTimeout(() => cb(result), timeout || TIMEOUT)
    getProducts(result => console.log(result)) //console.log可以是任意处理result的函数

// compose(fn1,fn2,fn3) 变为
// fn1(fn2(fn3))

export function compose(...funcs){
	if (funcs.length==0) {
		return arg=>arg
	}
	if (funcs.length==1) {
		return funcs[0]
	}
	return funcs.reduce((ret,item)=> (...args)=>ret(item(...args)))
}

const inBrowser = typeof window !== 'undefined'
const UA = inBrowser && window.navigator.userAgent.toLowerCase()


const isIE = UA && /msie|trident/.test(UA)
const isIE9 = UA && UA.indexOf('msie 9.0') > 0
const isEdge = UA && UA.indexOf('edge/') > 0
const isAndroid = UA && UA.indexOf('android') > 0
const isIOS = UA && /iphone|ipad|ipod|ios/.test(UA)
const isChrome = UA && /chrome\/\d+/.test(UA) && !isEdge

function hasClass(el, className) {
  let reg = new RegExp('(^|\\s)' + className + '(\\s|$)')
  return reg.test(el.className)
}

function addClass(el, className) {
  if (hasClass(el, className)) {
    return
  }

  let newClass = el.className.split(' ')
  newClass.push(className)
  el.className = newClass.join(' ')
}

function removeClass (obj, cls) {
  if (hasClass(obj, cls)) {
    const reg = new RegExp('(\\s|^)' + cls + '(\\s|$)');
    obj.className = obj.className.replace(reg, ' ');
  }
};

function toggleClass(obj, cls) {
  if (hasClass(obj, cls)) {
    removeClass(obj, cls);
  } else {
    addClass(obj, cls);
  }
};

/AppleWebKit.*Mobile/i.test(navigator.userAgent) || /Android|iPhone|Windows Phone|webOS|iPod|BlackBerry/i.test(navigator.userAgent)

  const pipeAsyncFunctions = (...fns) => arg => fns.reduce((p, f) => p.then(f), Promise.resolve(arg))

  const sum = pipeAsyncFunctions(
    x => x + 1,
    x => new Promise(resolve => setTimeout(() => resolve(x + 2), 1000)),
    x => x + 3,
    async x => (await x) + 4
  )


  sum(5).then(res => {
    console.log("111", res)
  })

  const promisify = func => (...args) =>
    new Promise((resolve, reject) =>
      func(...args, (err, result) => (err ? reject(err) : resolve(result)))
    );

  const delay = promisify((d, cb) => setTimeout(cb, d));

  delay(2000).then(() => console.log('Hi!')); // // Promise resolves after 2s

    var getSingle = function (fn) {
        var result
        return function () {
            return result || (result = fn.apply(this, arguments))
        }
    }

  var createLoginLayer = function () {
        var div = document.createElement('div')
        div.innerHTML = 'aaaa'
        document.body.appendChild(div)
        return div
    }

    var createSingleLoginLayer = getSingle(createLoginLayer)

    createSingleLoginLayer()
    createSingleLoginLayer()
    createSingleLoginLayer()

    const csvFileLine = '1997,John Doe,US,john@doe.com,New York';
    const {2: country, 4: state} = csvFileLine.split(',');
    console.log(country, ' --- ', state)  //US  ---  New York

    const csvFileLine = '1997,John Doe,US,john@doe.com,New York,New York1,New York2';
    const [, , country, , state] = csvFileLine.split(',');
    console.log(country, ' --- ', state)  //US  ---  New York

const ADDRESS = 'One Infinite Loop, Cupertino 95014';
const CITY_ZIP_CODE_REGEX = /^[^,\\]+[,\\\s]+(.+?)\s*(\d{5})?$/;
const [, city, zipCode] = ADDRESS.match(CITY_ZIP_CODE_REGEX) || [];
saveCityZipCode(city, zipCode);

var a = true, b = false, c = false;
console.log( a || b && c )  // true
console.log( (a || b) && c ) // false
console.log( a || (b && c) )  // true

mround = function (r) { 
  return parseInt(Number(r)||0);
} 

var quickExpr = /^[^<]*(<(.|\s)+>)[^>]*$|^#(\w+)$/

  function parseTime(time, cFormat) {
    if (arguments.length === 0) {
      return null
    }
    const format = cFormat || '{y}-{m}-{d} {h}:{i}:{s}'
    let date
    if (typeof time === 'object') {
      date = time
    } else {
      if (('' + time).length === 10) time = parseInt(time) * 1000
      date = new Date(time)
    }
    const formatObj = {
      y: date.getFullYear(),
      m: date.getMonth() + 1,
      d: date.getDate(),
      h: date.getHours(),
      i: date.getMinutes(),
      s: date.getSeconds(),
      a: date.getDay()
    }
    const time_str = format.replace(/{(y|m|d|h|i|s|a)+}/g, (result, key) => {
        // result 匹配模式的字符串 如:{y}
        // key 模式中的子表达式匹配的字符串 如：y 可以有 0 个或多个这样的参数
        // 接下来的参数是一个整数，声明了匹配在 stringObject 中出现的位置。  stringObject.replace(regexp/substr,replacement)
        // 最后一个参数是 stringObject 本身。
      let value = formatObj[key]
      if (key === 'a') return ['一', '二', '三', '四', '五', '六', '日'][value - 1]
      if (result.length > 0 && value < 10) {
        value = '0' + value
      }
      return value || 0
    })
    return time_str
  }


  let res = parseTime(new Date())
  console.log(res) //2018-07-22 22:08:23

/**
 * This is just a simple version of deep copy
 * Has a lot of edge cases bug
 * If you want to use a perfect deep copy, use lodash's _.cloneDeep
 */
export function deepClone(source) {
  if (!source && typeof source !== 'object') {
    throw new Error('error arguments', 'shallowClone')
  }
  let targetObj = source.constructor === Array ? [] : {}
  Object.keys(source).forEach((key) => {
    if (source[key] && typeof source[key] === 'object') {
      targetObj[key] = deepClone(source[key])
    } else {
      targetObj[key] = source[key]
    }
  })
  return targetObj
}

var broadcast = {
  on: function(name, fn) {
    var data = broadcast.data
    if (data.hasOwnProperty(name)) {
      data[name].push(fn)
    } else {
      data[name] = [fn]
    }
    return this
  },
  fire: function(name, data, thisArg) {
    var fnList = broadcast.data[name] || []
    for (i = 0, len = fnList.length; i < len; i++) {
      fnList[i].apply(thisArg || null, [data, name])
    }
    return this
  },
  data: {}
}

  // test
  broadcast.on('showRiding', ()=>{console.log('showRiding')})
  broadcast.fire('showRiding') // showRiding

const compact = arr => arr.filter(Boolean)
compact([0, 1, false, 2, '', 3, 'a', 'e' * 23, NaN, 's', 34])             // [ 1, 2, 3, 'a', 's', 34 ]

Math.floor(4.9) === 4      //true
// 简写为：
~~4.9 === 4      //true

~~4.5            // 4
Math.floor(4.5)        // 4
~~-4.5        // -4
Math.floor(-4.5)        // -5

1.3 | 0         // 1
-1.9 | 0        // -1

~~true == 1
~~false == 0
~~"" == 0
~~[] == 0
~~undefined ==0
~~!undefined == 1
~~null == 0
~~!null == 1

比如 ~~10.2323=10
~~（10/3） = 3

async function getFullPost(){
  return await Promise.all([
     fetch('/post'),
     fetch('/comments')
  ]);
}
const [post, comments] = getFullPost();

  function param2Obj(url) {
    const search = url.split('?')[1]
    if (!search) {
      return {}
    }
    // 将字符串转成json对象
    return JSON.parse('{"' + decodeURIComponent(search).replace(/"/g, '\\"').replace(/&/g, '","').replace(/=/g, '":"') + '"}')
  }
  console.log(param2Obj('https://www.aaa.com?aaa=111&bbb=222'))
  // {aaa: "111", bbb: "222"}

/**
 * Checks if the passed element is dom object or not
 */
export const isDomElement = function (element) {
  return element && typeof element === 'object' && 'nodeType' in element;
};

/**
 * Turn a string into a node
 * @param  {String} htmlString to convert
 * @return {Node}   Converted node element
 */
const createNodeFromString = (htmlString) => {
  const div = document.createElement('div');
  div.innerHTML = htmlString.trim();

  // Change this to div.childNodes to support multiple top-level nodes
  return div.firstChild;
};

  function reverseStr(str) {
    return str.split('').reverse().join('')
  }

var a = 'foo'
Array.prototype.reverse.call( a );
// 返回值仍然是字符串"foo"的一个封装对象 (这种办法是行不通的)

 let str = 'xxx'
 /^[\u4E00-\u9FA5]+$/.test(str)

function normalizeMap (map) {
    return Array.isArray(map)
      ? map.map(key => ({key, val: key}))
      : Object.keys(map).map(key => ({key, val: map[key]}))
  }

  normalizeMap(['a', 'b']) //[{key: "a", val: "a"},{key: "b", val: "b"}]
  normalizeMap({a: 'aaa', b: 'bbb'}) //[{key: "a", val: "aaa"},{key: "b", val: "bbb"}]

function newApply(Fn, argsAry) {
    argsAry.unshift(null);
    return new (Fn.bind.apply(Fn, argsAry));
}

// 调用
newApply(Cls.func, [1, 2, 3]) // well done !!

function cached(fn) {
    let cache = Object.create(null);
    return function cachedFn(str) {
        let hit = cache[str];
        return hit || (cache[str] = fn(str))
    }
}

let camelizeRE = /-(w)/g;
function camelize(str) {
    return str.replace(camelizeRE, function(_, c) {
        return c ? c.toUpperCase() : '';
    })
}
//ab-cd-ef ==> abCdEf
//使用记忆函数
let _camelize = cached(camelize)

let hyphenateRE = /B([A-Z])/g;
function hyphenate(str){
    return str.replace(hyphenateRE, '-$1').toLowerCase()
}
//abCd ==> ab-cd
//使用记忆函数
let _hyphenate = cached(hyphenate);

function capitalize(str){
    return str.charAt(0).toUpperCase() + str.slice(1)
}
// abc ==> Abc
//使用记忆函数
let _capitalize = cached(capitalize)

function extend(to, _from) {
    for(let key in _from) {
        to[key] = _from[key];
    }
    return to
}

['contextmenu', 'selectstart', 'copy'].forEach(function(ev){
    document.addEventListener(ev, function(event){
        return event.returnValue = false
    })
});

document.addEventListener('keydown', function(event){
    return !(
        112 == event.keyCode || //F1
        123 == event.keyCode || //F12
        event.ctrlKey && 82 == event.keyCode || //ctrl + R
        event.ctrlKey && 78 == event.keyCode || //ctrl + N
        event.shiftKey && 121 == event.keyCode || //shift + F10
        event.altKey && 115 == event.keyCode || //alt + F4
        "A" == event.srcElement.tagName && event.shiftKey //shift + 点击a标签
    ) || (event.returnValue = false)
});

/**
 * 按循序执行 Promise 任务
 * @param {Array} options.tasks 要执行的任务队列
 * @param {Host} options.thisIns 宿主实例
 * @param {*} options.arg 透传的参数
 */
function sequenceTasks({ tasks, thisIns, arg }) {
    function recordValue(results, value) {
        results.push(value);
        return results;
    }
    const pushValue = recordValue.bind(null, []);
    return tasks.reduce(
        (promise, task) => promise
            .then(() => task.apply(thisIns, arg))
            .then(pushValue),
        Promise.resolve(),
    );
}

  function recordValue(results, value) {
    results.push(value);
    return results;
  }

  const pushValue = recordValue.bind(null, []);


  pushValue('111')
  pushValue('222')
  pushValue('333')
  let res = pushValue('444')


  console.log(res)  //["111", "222", "333", "444"]

function.bind(thisArg[, arg1[, arg2[, ...]]])

class Login {
  static _loginSingleton = null; //正在进行的登录流程
  
  static async _login(){
    //登录流程...
  }
  
  //封装了免并发逻辑的登录函数
  static async login(){
    if (Login._loginSingleton) //若当前有登录流程正在进行，则直接使用其结果作为本次登录结果
        return Login._loginSingleton;
        
    //否则触发登录流程
    Login._loginSingleton = Login._login();
    
    //并在登录结束时释放并发限制
    Login._loginSingleton.then(()=>{Login._loginSingleton = null}).catch(()=>{Login._loginSingleton = null});
    
    //返回登录结果      
    return Login._loginSingleton;
  }
}

async function getAdListByRequest(data = {}) {
  return new Promise(async (resolve, reject) => {
    global.singleton = global.singleton || {};
    global.singleton[AD_LIST_KEY + 'lock'] = global.singleton[AD_LIST_KEY + 'lock'] || false;
    if (global.singleton[AD_LIST_KEY + 'lock']) {
      global.singleton[AD_LIST_KEY].push(resolve);
    } else {
      global.singleton[AD_LIST_KEY + 'lock'] = true;
      // console.log('singleton start', '1');
      global.singleton[AD_LIST_KEY] = [resolve];
      _getAdListForPure(data).then((output) => {
        // ....
        let func = {};
        // eslint-disable-next-line
        while (func = global.singleton[AD_LIST_KEY].shift()) {
          func(output.data.data);
          // console.log('singleton end', output);
        }
        global.singleton[AD_LIST_KEY + 'lock'] = false;
      }, rej => {
        reject(rej);
      });
    }
  });
}

  let obj = {
    aaa: 'aaa'
  }


  obj.aaa = Object.defineProperty(function () {
      console.log('this', this)
      console.log('aaaa')
    },
    'xxxx',
    {value: true}
  )


  console.log(obj.aaa())  //this {aaa: ƒ}   aaaa

  console.log(obj.aaa)
  /**
   * () => {
   * console.log('this', this)
   * console.log('aaaa')
   * }
   */


  console.log(obj.aaa.xxxx)  //true

    theHost[funName] = Object.defineProperty(
        function pluggableHookFun(...arg) {
            const _theHost = this;

            if (typeof beforeCall === 'function') beforeCall({ theHost: _theHost });

            const funQueue = _theHost.getHookFunQueue(funName);

            // 如果不存在，则 resolve
            if (!funQueue || !Array.isArray(funQueue)) return Promise.resolve();

            // 以 「先进先出」 的形式按顺序执行 Promise 链，未捕捉的错误，扔到 onError 去。
            return sequenceTasks({
                tasks: funQueue,
                thisIns: _theHost,
                arg,
            }).catch((err) => {
                if (typeof _theHost.onError === 'function') {
                    _theHost.onError(err);
                }
                throw err;
            });
        },
        'isPluggableHookFun', { value: true },
    );

  const htmlToString = (str) => {
    let divEle = document.createElement('div')
    divEle.innerHTML = str
    return divEle.innerText
  }


  let str = "<p>qwe<span>asd</span>qwe</p>"
  
  console.log(htmlToString(str))   //qweasdqwe

  let obj = {
    aaa: ''
  }

  if (obj.aaa) {
    console.log("含有此属性")   //无法打印
  }

  let obj = {
    // aaa: null
    // aaa:""
    aaa: undefined
  }

  if (obj.hasOwnProperty("aaa")) {
    // 上面三种情况 均可以console到
    console.log("含有此属性")
  }

<script type="text/javascript">
  x = document.getElementById("intro");
  console.log(x.firstChild.nodeValue);  //  Hello World!
</script>

const ary = (fn, n) => (...args) => fn(...args.slice(0, n));

EXAMPLES

const firstTwoMax = ary(Math.max, 2);
[[2, 6, 'a'], [6, 4, 8], [10]].map(x => firstTwoMax(...x)); // [6, 6, 10]

var extend = function extend() {
  var target = arguments[0] || {};
  var i = 1;
  var length = arguments.length;
  var deep = false;
  var options, name, src, copy, copyIsArray, clone;

  // Handle a deep copy situation
  if (typeof target === 'boolean') {
    deep = target;
    target = arguments[1] || {};
    // skip the boolean and the target
    i = 2;
  }

  // Handle case when target is a string or something (possible in deep copy)
  if (typeof target !== 'object' && !is.fn(target)) {
    target = {};
  }

  for (; i < length; i++) {
    // Only deal with non-null/undefined values
    options = arguments[i];
    if (options != null) {
      if (typeof options === 'string') {
        options = options.split('');
      }
      // Extend the base object
      for (name in options) {
        src = target[name];
        copy = options[name];

        // Prevent never-ending loop
        if (target === copy) {
          continue;
        }

        // Recurse if we're merging plain objects or arrays
        if (deep && copy && (is.hash(copy) || (copyIsArray = is.array(copy)))) {
          if (copyIsArray) {
            copyIsArray = false;
            clone = src && is.array(src) ? src : [];
          } else {
            clone = src && is.hash(src) ? src : {};
          }

          // Never move original objects, clone them
          target[name] = extend(deep, clone, copy);

        // Don't bring in undefined values
        } else if (typeof copy !== 'undefined') {
          target[name] = copy;
        }
      }
    }
  }

  // Return the modified object
  return target;
};

Function.prototype.getName = function(){
    return this.name || this.toString().match(/function\s*([^(]*)\(/)[1]
}

  console.log(new Date())
  // Fri Nov 15 2019 14:19:36 GMT+0800 (中国标准时间)
  console.log(+new Date())
  // 1573798776557