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));

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