const toDecimalMark = num => num.toLocaleString("en-US");

console.log(toDecimalMark(12305030388.9087))

const setTime = tiemStamp => new Date(parseInt(timeStamp) * 1000).toLocaleString().replace(/[/]/g,'-');

console.log(setTime(1535932800))

const timeStamp = time => new Date(time).getTime();

console.log(timeStamp('2019-03-19 11:55:00'))

const removeSpace = str => str.replace(/\s+/g,'')

let str = '1 2 3 4'

console.log(removeSpace(str))

const typeOf = str=> Object.prototype.toString.call(str) == '[object String]'

let str = '3123'

console.log(typeOf(str))

function unitConvert(num){

    let moneyUnits = ['元','万元','亿元','万亿'];

    let dividend = 10000;

    let curentNum = num; //转换数字

    let curentUnit = moneyUnits[0]; //转换单位

    let len = moneyUnits.length;

    for(var i = 0; i < len; i++) {

        curentUnit = moneyUnits[i];

        if(strNumSize(curentNum) < 5) {

            break;

        }

        curentNum = curentNum / dividend;

    }

    let m = {num: 0,unit: ""}

    m.num = curentNum.toFixed(2);

    m.unit = curentUnit;

    return m;

}

function strNumSize(tempNum) {

    var stringNum = tempNum.toString();

    var index = stringNum.indexOf(".");

    var newNum = stringNum;

    if(index != -1) {

        newNum = stringNum.substring(0, index);

    }

    return newNum.length;

}

unitConvert(1000000)

(1)

let arrList = [1,2,3,1,3,33,6,2];

const removeRepeat = arr => [...new Set(arr)]

console.log(removeArr(arrList))

(2)

let arrList = [1,2,3,1,3,33,6,2];

let newArr = [];

let len = arrList.length

for(let i=0;i<len;i++){

    newArr.indexOf(arrList[i])==-1 ? newArr.push(arrList[i]):''

}

console.log(newArr)

let str = "qwertyuiopqqqasdf"

function maxstringload(str){

    let obj = {}

    let len = str.length

    for(let i=0;i<str.len;i++){

        let key = str[i]

        if(obj[key]){

            obj[key]++

        }else{

            obj[key] = 1

        }

    }

    let maxCount =0;

    let maxString = "";

    for(let key in obj){

        if(maxCount<obj[key]){

            maxCount = boj[key];

            maxString = key;

        }

    }

    return "出现次数最多的字母:" + maxString + "出现了" + maxCount + "次";

}

console.log(maxstringload(str))

(1)

let arr = [17,2,47,3,5,9,3,4,11,4,24]

const sortArr = arr => arr.sort((prve,next) => prve-next);

console.log(arr)

(2)

function bubbleSort(arr) {

    let len = arr.length;

    for(let i = 0; i < len; i++) {

        for(let j = 0; j < len - 1 - i; j++) {

            if(arr[j] > arr[j + 1]) { //相邻元素两两对比,如果前一个数比后一个大，就交换位置

                let temp = arr[j + 1]; //元素交换

                arr[j + 1] = arr[j];

                arr[j] = temp;

            }

        }

    }

    return arr;

}

let arr = [3, 44, 38, 5, 47, 15, 36, 26, 27, 2, 46, 4, 19, 50, 48];

console.log(bubbleSort(arr));

(1)
const clone = obj => obj.JSON.parse(JSON.stringify(obj));

const clone = obj => obj.JSON.stringify(JSON.parse(obj))


(2)

const perfectClone = obj => {

    if(obj == null){

        return 'unKonwn';

    }

    if(typeof obj !== 'object'){

        return obj

    }

    if(obj.constructor === Date){

        return new Date(obj)

    }

    const newObj = new obj.constructor();

    for(let key in obj){

        if(obj.hasOwnProperty(key)){

            const val = obj[key]

            newObj[key] = typeof val === 'object' ? argument.call(val) : val;

        }

    }

    return newObj

}

const shallowClone = obj => Object.assign({},obj)

Math.random();//随机生成0到1的数字

Math.floor(Math.random() * 可能只的总数 + 第一个可能的值)

eg:Math.floor(Math.random() * 9 + 2); // 生成2到10的值，包括2和10

即：

Math.floor(Math.random()*(最大值 - 最小值 +1) + 最小值);//随机生成[n,m]的随机整数

function flat(arr){

    let newArr = [];

    let len = arr.length

    for(let i=0;i<len;i++){

        if (Array.isArray(arr[i])) {

            newArr = newArr.concat(flat(arr[i]));

        }else{

            newArr.push(arr[i])

        }
　　 }

    return newArr

}

let arr = [1,2,[3,4,[5,6],7],8,9];

console.log(flat(arr))