js小仓库

1、千分位分隔符

const toDecimalMark = num => num.toLocaleString("en-US");
console.log(toDecimalMark(12305030388.9087))

2、时间戳转时间

const setTime = tiemStamp => new Date(parseInt(timeStamp) * 1000).toLocaleString().replace(/[/]/g,'-');
console.log(setTime(1535932800))

3、时间转时间戳

const timeStamp = time => new Date(time).getTime();
console.log(timeStamp('2019-03-19 11:55:00'))

4、去除空格

const removeSpace = str => str.replace(/\s+/g,'')
let str = '1 2 3 4'
console.log(removeSpace(str))

5、检测类型

const typeOf = str=> Object.prototype.toString.call(str) == '[object String]'
let str = '3123'
console.log(typeOf(str))

 6、数字简化为“万”

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)

7、数组去重

(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)

8、出现最多次数的字符串，出现多少次

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))

9、数组排序

(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));

 10、深拷贝

(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
}

11、浅拷贝

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

 12、随机数

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

　　

 13、数组扁平化

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))

 

 

待续。。。