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Javascript – I dont how to use "path" in app.use(). It gives me a result that I was not expected

I am new in express.js and I want to know how to use "path" in app.use() excatly. When I try the code which is following, I get a result but I am so confusing. Can you explain why the result is like that. Thank you so much.

My code is following:

const express = require('express');
const router = express.Router()
const app  = express();
const port = 3000;

app.listen(port, ()=>{
    console.log("Running");
})

app.use("/test",router)
// app.use()


router.get("/test",(req,res,next)=>{
    console.log("test 1");
    console.log(req.originalUrl);
    next()
})


router.get("/",(req,res,next)=>{
    console.log("first /");
    console.log(req.originalUrl);
    next()
})
router.get("/test",(req,res,next)=>{
    console.log("test 2");
    console.log(req.originalUrl);
    next()
})

router.get("/",(req,res,next)=>{
    console.log("second /");
    console.log(req.originalUrl);
    next()
})

And, I did test in "http://localhost:3000/test" but the result is not as I expected. Console output is :

first /
/test
second /
/test

But I was expected that result will be

test 1
/test
test 2
/test

Why is it like that? Could you explain to me? Thank you so much.

Tags:

2

Answers


  1. 0 
    const express = require('express');
const router = express.Router();
const app = express();
const port = 3000;


router.get("/", (req, res, next) => {
    console.log("test 1");
    console.log(req.originalUrl);
    next(); 
});

router.get("/", (req, res, next) => {
    console.log("test 2");
    console.log(req.originalUrl);

});

app.use("/test", router);

app.listen(port, () => {
    console.log("Running on port", port);
});

    This discrepancy occurs because router.get("/test",...) is actually looking for a path of /test/test due to the way routers are nested and paths are interpreted in Express.js. Since such a path is not defined in your setup, the request to /test is handled by the routes mounted at /test and defined as / within the router, not the ones looking for /test within the router.

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  2. 0

    The output you’re seeing is correct based on the current implementation.

    Currently you have the following top level routes defined in your instance:

    localhost:3000/test
    localhost: 3000/test/test

    Under the /test route you’ve setup two functions / middleware:

    #1 – first /
    #2 – second /

    Under the /test/test route you currently have another two functions / middleware setup:

    #1 – test 1
    #2 – test 2

    Perhaps restructuring the code (shown below) can help visualize the order in which the request will be handled based on the route:

    router.get("/test",(req,res,next)=>{
    console.log("test 1");
    console.log(req.originalUrl);
    next()
})

router.get("/test",(req,res,next)=>{
    console.log("test 2");
    console.log(req.originalUrl);
    next()
})

router.get("/",(req,res,next)=>{
    console.log("first /");
    console.log(req.originalUrl);
    next()
})

router.get("/",(req,res,next)=>{
    console.log("second /");
    console.log(req.originalUrl);
    next()
})
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