关于javascript:常用Js函数

1.判断是不是数组

function isArray(arr){    return typeof Array.isArray === 'function' ? Array.isArray(arr) : Object.prototype.toString.call(arr) === "[object Array]"}

2.判断是否对象

function isObject(obj) {     return Object.prototype.toString.call(obj) === '[object Object]'}

3.判断是不是字符串

function isString(str){    return Object.prototype.toString.call(str)=="[object String]"}

4.数组依据元素的某个KEY排序

// 数组排序function arraysort(attr, rev) {    if (rev == undefined) {        rev = 1;    }    return function (a, b) {        a = a[attr];        b = b[attr];        if (a < b) {            return rev * -1;        }        if (a > b) {            return rev * 1;        }        return 0;    }}arr.sort(arraysort('totalInv',-1))

5.格式化工夫

function dateFormater(formater, t){    let date = t ? new Date(t) : new Date(),        Y = date.getFullYear() + '',        M = date.getMonth() + 1,        D = date.getDate(),        H = date.getHours(),        m = date.getMinutes(),        s = date.getSeconds();    return formater.replace(/YYYY|yyyy/g,Y)        .replace(/YY|yy/g,Y.substr(2,2))        .replace(/MM/g,(M<10?'0':'') + M)        .replace(/DD/g,(D<10?'0':'') + D)        .replace(/HH|hh/g,(H<10?'0':'') + H)        .replace(/mm/g,(m<10?'0':'') + m)        .replace(/ss/g,(s<10?'0':'') + s)}