NodeJS / Express: what is “app.use”?

Question

In the docs for the NodeJS express module, the example code has app.use(...).

What is the use function and where is it defined?

Answer 1

app.use is woks as middleware for app request. syntax

app.use('pass request format',function which contain request response onject)

example

app.use('/',funtion(req,res){
 console.log(all request pass through it);
// here u can check your authentication and other activities.
})

also you can use it in case of routing your request.

app.use('/', roting_object);