The configuration required for the project is as follows

First step ：node Project initialization

npm init --yes
nom i express
nom i cors

The second step ： download npm Tripartite package express If you want to cross domain, you need to download cors

The overall project segment status is as follows

  testApi-demo              #  Project directory 
    ├── node_modules        #  Third party packages that the project depends on 
    └── routers             # new express.Rouer()
        └── jokeRouter.js      # route 
    ├── data                #  Imitate database ,
        └── jokes.json         #  Joke data ： What is stored is an array 
    ├── package.json        #  Describe the project and the project 
    ├── package-lock.json   #  Project package version locking and download address 
    ├── app.js              # node Entrance file 
    ├── controller          #  obtain data Data in 
        └── jokelnfo           # 

The first part ：get request （ Simple key value pairs ）

First step ： stay app.js Middle configuration

// I have not set up cross domain 
const express = require('express')
//2. Create a server 
const app = express()

//  Import cors Allow cross-domain 
//const cors = require('cors')

//  Import joke route 
const joke = require('./routers/jokeRouter.js')
//  stay app.js Mount in 
app.use('/joke',joke)

//  Use cors Set allow cross domain 
//app.use(cors())

//3. Turn on the server 
app.listen(3000,()=>{
console.log('success')
})

 Access address  172.0.0.1:3000/joke?num=1

The second step ： stay routers/jokeRouter.js Middle configuration  

//  Import express
const express = require('express')
//  Import the data ready to respond to the front end 
const joke = require('../controller/jokeInfo.js')
const router = new express.Router()
router.get('/',joke)
module.exports = router

//  Be careful ：
// module.exports be used for node Module block development , Export a module , Corresponding import require(‘xxx modular ’)
// export default be used for ES6 Module block development , Export a module , Corresponding import import XXX from 'xxx modular ’

The third step ： stay controller/jokelnfi.js The data transmitted to the front end is set in the controller

It is judged that the writing is not quite right ： That's about it

// Import me in data Data in 
const dataJokes = require('../data/jokes.json') 

function joke(req,res){
  //  This is random data 
  //  The length of the array 489, Send one randomly 
  // req.query Simple key value pairs get Request to get the data from the client 
  if(req.query.num){
      function produceNum(n){
          let arr=[]
          let sum = []
          for(let i = 1; i<=n;i++){
              sum.push(dataJokes[parseInt(Math.random()*489)]) 
              if(arr.indexOf([parseInt(Math.random()*489)])===-1){
                  arr.push([parseInt(Math.random()*489)])
               }else{
                  i--
               }
          }
          return sum
      }
      res.send({
          status:0,
          message:" Get user list data successfully ",
          data:produceNum(req.query.num)
      })
        

    }else if(req.query instanceof Object){
        res.send({
            status:0,
            message:" Get user list data successfully ",
            data:dataJokes[parseInt(Math.random()*489)]
        })
    }
    // console.log(dataJokes[parseInt(Math.random()*489)])
    
}
module.exports = joke