js-小技巧和小方法

1.字符串首字母大写

var str="xiamgfafsfsfdsf fdsfsfsf"
str = str.substring(0,1).toUpperCase()+str.substring(1);
console.log(str) //Xiamgfafsfsfdsf fdsfsfsf

2.创建一个随机的id

function createRandomId() {
return (Math.random() * 10000000).toString(16).substr(0, 4) + ‘-‘ + (new Date()).getTime() + ‘-‘ + Math.random().toString().substr(2, 5);
}

3.日期排序

function sortDownDate(a, b) {
return Date.parse(a.dates) - Date.parse(b.dates);
}

function sortUpDate(a, b) {
return Date.parse(b.dates) - Date.parse(a.dates);
}
var arr=[
{
sender: "a",
dates: "2017-08-18 13:23:21",
age: "21"
},
{
sender: "a",
dates: "2017-03-18 19:23:21",
age: "22"
},
{
sender: "a",
dates: "2015-08-18 13:23:21",
age: "22"
},
{
sender: "a",
dates: "2018-01-18 12:12:12",
age: "56"
},
{
sender: "b",
dates: "2011-02-18 13:23:21",
age: "22"
},
{
sender: "b",
dates: "2011-08-18 3:3:3",
age: "22"
},
{
sender: "c",
dates: "2017-01-18 13:23:21",
age: "22"
},
{
sender: "elson",
dates: "2017-08-18 6:6:6",
age: "34"
},
{
sender: "lon",
dates: "2017-02-18 13:23:21",
age: "22"
},
{
sender: "lon",
dates: "2017-04-18 13:23:21",
age: "22"
},
{
sender: "son",
dates: "2017-06-18 13:23:21",
age: "22"
},
{
sender: "on",
dates: "2017-08-18 13:23:21",
age: "22"
},
];

console.log(arr.sort(sortDownDate));//正序
console.log(arr.sort(sortUpDate));//反序

4.

js-小技巧和小方法

原文：https://www.cnblogs.com/xiao-peng-ji/p/11636107.html