"callback" argument must be a function

Question

最后一句话报错,scraper()是一个爬虫函数，但是因为网站对请求频率有限制，所有要定时执行。

var request = require('request'),
    cheerio = require('cheerio'),
    http = require('http'),
    url = require('url'),
    mysql = require('mysql');
    
var id=22535;

var title;
var news = [];

function scraper (id) {

    var host = 'http://www.sosobtc.com/article/'+id+".html";
  request(host, function (error, response, data) {
    if (!error && response.statusCode == 200) {
      var $ = cheerio.load(data);
     title = $('.article-header h2').text();
      var time=$('.timestamp').first().text();
        var content=$('.article-main').text();
      var myDate=new Date();
      
      //存入数据库

var connection = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: '134679852a',
    database:'news'
});

connection.connect();


//增加数据
var sql="insert into news(title,content,time) values(?,?,?)";
var sql_params=[title,content,myDate.toLocaleDateString()+'的'+time];
connection.query(sql,sql_params,function(err,result){
     if(err){
         console.log('[INSERT ERROR] - ',err.message);
         return;
        }
            console.log("success !!!  "+id);
});

//关闭连接
connection.end();  
    
    }
    else console.log("page not found!"+id);
  });
  id--;
}
    if(id<10002) {
        console.log("finished");
        clearInterval(stopid);
    }
    
var stopid=setInterval(scraper(id),100);

Answer 1

var stopid=setInterval(scraper(id),100);
改成
var stopid=setInterval(scraper,100,id);
要不然,你这样写是没效果的

Answer 2

意思就是，scraper(id)返回的不是一个function对象，而setInterval的第一个参数需要是一个方法。试试改写为var stopid=setInterval(()=>scraper(id),100);