Post method in each route of express

at the beginning of learning node+express, there is a question that is not very clear. I would like to ask you a question:

after a new express project is created by default, there are two pages: index and user
I need to write a post interface in the user page:

clipboard.png
ajax404 Not Found

clipboard.png

clipboard.png
, but if I put the post API test in user.js into the ingress page index.js, and then call it in user.jade, it will work normally.
I would like to ask:
whether all APIs need to be placed on the ingress page before they can be called; what should I do if I want to put them in different routes?

= Thank you for your great solution =

Express node.js
Mar.17,2021

how do you router use ?
app.use ('/ name',router)
then your route is / name/test

router = export.Router () is a convenient (universal prefix) operation, as well as a convenient modular operation. You need to hang router under app.

app.use ('/', router) , if the slash is replaced with another prefix, as described on the first floor 

//routert.js
router.get('/', function(req, res) {
  
});
router.post('/test', function(req, res) {
});

//nodejs run js,app.js

//
var app = express();
var router = require('./router');
...
app.use('/user', router );
// /user /user/test

ide/routing.html" rel=" nofollow noreferrer "> http://www.expressjs.com.cn/g.

Previous: How to change the path of introducing resources into the index page of a vue-cli packaged project?

Next: The audio src, of the vkey obtained by QQ Music API can be played normally at the beginning, and it is 403 today. Excuse me, how can we be normal?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b36325-2ad3b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b36325-2ad3b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?