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.数组根据元素的某个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.格式化时间

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)
}