How to get requested page (node.js)

I am working with Node.js servers. When I log on to the server, the code,
res.write("What ever text you choose")
will run and I will only get the “What ever text you choose” no matter what path I type. I know you can “write” a file so every time you log on to the server, it will give you that page. The problem I am having is that the server will only give me the one file. How can I request a different file based on the URL?

For example, When I type in localhost:9090, I’ll get the file I requested.
But if I type in localhost:9090/index.html or localhost:9090/funnyFile/Jokes.html or localhost:9090/myProjects/poj1/index.html, I’ll just get the same file, how can I access funnyFile and myProjects?

Here is my node server’s code.

const http = require('express')
const port = 9090

// Create a server object:
const server = http.createServer(function (req, res) {

    // Write a response to the client
    res.write("I choose this text");
    

    // End the response 
    res.end()
})

// Set up our server so it will listen on the port
server.listen(port, function (error) {

    // Checking any error occur while listening on port
    if (error) {
        console.log('Something went wrong', error);
    }
    // Else sent message of listening
    else {
        console.log('Server is listening on port' + port);
    }
})