An Express application can use the following types of middleware:
Application-level middleware
Router-level middleware
Error-handling middleware
Built-in middleware
Third-party middlewarevar express = require('express')
var app = express()
var myLogger = function (req, res, next) {
console.log('LOGGED')
next()
}
app.use(myLogger)
app.get('/', function (req, res) {
res.send('Hello World!')
})//4 types of middleware document,query,aggregate and model
//document middleware run before .save() and .create()
const slugify = require('slugify')
tourSchema.pre('save',function(next) {
console.log('will save document')
this.slug= slugify(this.name,{lower:true})
next()
})const requestLogger = (request, response, next) => {
console.log('Method:', request.method)
console.log('Path: ', request.path)
console.log('Body: ', request.body)
console.log('---')
next()
}
app.use('/user/:id', (req, res, next) => {
console.log('Request Type:', req.method)
next()
})