限制limit

1.cmd输入limit为字段 skip为下标

//limit(2)  只会获取两条数据
db.top250.find().limit(2)
//skip()  下标
db.top250.find().skip(1).limit(2)

2.前端处理limit和下标

http://localhost:8080/top250?start=0&count=5;
start-->为下标
count-->为限制

3.index.js

router.get("/top250",async ctx=>{
    console.log(ctx.query)
    var {start,count} = ctx.query
    console.log(start)
    if(start==undefined){
        start = 0
    }
    if(count == undefined){
        count = 5
    }
    var data = await Top250Model.find({}).skip(Number(start)).limit(Number(count));
    ctx.body = {
        data,
        code:200
    }
})