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。。。

 

转载于:https://www.cnblogs.com/YAN-HUA/p/10557752.html

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