Node.js中做定时任务

用node-cron这个库：https://github.com/kelektiv/node-cron

例子：

//import {CronJob} from 'cron';
const CronJob = require('cron').CronJob;

const job = new CronJob(
	'* * * * * *',  //cron time
	function(){
		console.log('You will see this message every second');
	},
	null,	//onComplete
	true,	//start
	'Asia/Shanghai'	//timeZone
);

job.start();

注：用import {CronJob} from 'cron'的时候报错SyntaxError: Cannot use import statement outside a module
Node.js用的是CommonJS的标准，而import是ES6的标准，所以这里要用require， 或者把.js扩展名改为.mjs，这样即可以兼容ES6，用import ... from 就不会报错了。

执行：node cron.js

node cron.js
You will see this message every second
You will see this message every second
You will see this message every second
You will see this message every second
......