Release monitor backend - 1
ECA Node/React - June 2019
Plan
- webservice with express
- middleware
- asynchronous
Project structure review
create a server
Not this way
// server.js
var http = require('http');
//create a server object:
http.createServer((req, res) => {
res.write('Hello World!'); //write a response to the client
res.end(); //end the response
}).listen(8080); //the server object listens on port 8080With Express
Install Express
npm i express --saveStart with hello world
const express = require('express')
const app = express()
const port = 3000
app.get('/', (req, res) => res.send('Hello World!'))
app.listen(port, () => console.log(`Example app listening on port ${port}!`))Design the API
Design the API
- GET /services/{env}
- POST /services
{
"env": "maui",
"service_name": "service-name"
}
[{
"service_name": "service-name",
"build_version": "2019-01-01-01-01-1234"
}]
let's go
want hot reloading?
npm i nodemon --save-dev
// package.json
"scripts": {
"local:dev": "nodemon index.js"
}middleware and routes
let's refactor
app.js
index.js
src
routers
asynchronous
callback
setTimeout/setInterval
promise
async/await
process.nextTick
How NodeJS handle asynchronous
eventloop
How NodeJS handle asynchronous
eventloop
Quiz
mix callback,promise,async/await,setTimeout
Http client - get base version
using axios
npm i axios --savehttps://floobits.com/yagong/backend
test
npm i --save-dev jest supertest
npm i --save-dev eslint-plugin-jest
install dependencies
test
// in package.json add this section
"jest": {
"testEnvironment": "node"
}
// in .eslintrc.js, add plugins:
'plugin:jest/recommended'configure jest
test with supertest
const app = require('../src/app')
const request = require('supertest')
it('should return hello world', async function() {
const response = await request(app).get('/hello-world')
expect(response.text).toEqual('hello world')
})
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