How to fix error while uploading a file using fetch?

Question

JavaScript

There is a server on node.js, after I follow the link to another page, I need to load the data from the json file into an array in js, I do it through fetch (), I saw on YouTube how the code worked, but the server code was not shown on the video etc. Here is the js code itself:

fetch("./data.json")
  .then(function(resp){
    return resp.json();
  })
  .then(function(data) {
    console.log(data);
  });

This is the node js code:

const http = require("http");
const fs = require("fs");

http.createServer((req, res) => {
  switch (req.url) {

    case '/': 
    const html = fs.readFileSync('index.html', 'utf8'); 
    res.writeHead(200, {'Content-Type': 'text/html'});
      res.end(html);

    case '/exmpl.js':
    const js = fs.readFileSync('exmpl.js', 'utf8'); 
    res.writeHead(200, {'Content-Type': 'text/javascript'});
  		res.end(js);	

    case '/Gistograma.html':
    const gist = fs.readFileSync('Gistograma.html', 'utf8'); 
    res.writeHead(200, {'Content-Type': 'text/html'});
      res.end(gist);

    case '/Gistogr.js':
    const gistjs = fs.readFileSync('Gistogr.js', 'utf8'); 
    res.writeHead(200, {'Content-Type': 'text/javascript'});
      res.end(gistjs);

      case '/server1.js':
    const server1 = fs.readFileSync('server1.js', 'utf8'); 
    res.writeHead(200, {'Content-Type': 'text/javascript'});
      res.end(server1);

  		default: 
  		res.writeHead(404, {'Content-Type': 'text/plain'});
  		res.end('ERROR 404');
  }
}).listen(3000, () => console.log('server is on'));

The js code is in server1.js and the node js is in server.js. All files are in one folder. Tell me what to do to read the contents of data.json. The error is thrown like this:

Answer 1

First, your server must be able to process a request for '/data.json'.
In the back part code you provided, requests for: '/', '/exmpl.js', '/Gistograma.html', '/Gistogr.js', '/server1.js' are processed. And in the default block, instructions are generally indicated that if a request comes for something else that is not included in this list, then respond with a 404 code - the standard HTTP response code, if the requested resource is not found.
Thus, if you add something like the following, then the problem should be solved:

case '/data.json':
    const js = fs.readFileSync('data.json', 'utf8'); 
    res.writeHead(200, {'Content-Type': 'application/json'});
  		res.end(js);