Dev Console got `http://localhost:3000/socket.io/socket.io.js is being assigned a //# sourceMappingURL, but already has one`

[xreider]

Describe the bug
Dev Console got http://localhost:3000/socket.io/socket.io.js is being assigned a //# sourceMappingURL, but already has one

To Reproduce

Socket.IO server version:"socket.io": "^4.1.2",

Server

const { io } = require('./app', {
  // allowEIO3: true, // false by default
});
io.on('connection', socket => {
  console.log('IO connected');
});

Socket.IO server version:"socket.io": "^4.1.2",

Client

client side pug

script(src='/socket.io/socket.io.js')
script.
  const socket = io();
  //- socket.on('hello', function (data) {
  //-   console.log(data);
  //- });
script(src='/bundles/bundle.js') // generated by web pack

[darrachequesne]

I guess that's because we have both:

• the sourcemap field in the bundle

socket.io/client-dist/socket.io.min.js

Line 7 in 1633150

//# sourceMappingURL=socket.io.min.js.map

• and the X-SourceMap header

socket.io/lib/index.ts

Line 521 in 1633150

res.setHeader("X-SourceMap", filename.substring(1) + ".map");

I think we could remove the header now.

[darrachequesne]

This should be fixed by a4dffc6, included in socket.io@4.1.3.

Thanks!