What is this hex value for in the Chrome debugger?

Question

I am just curious as to why there appears to be a hex number associated with each source in this Chrome debugger output here ...

WebSocket is already in CLOSING or CLOSED state.
(anonymous) @ websocket.js?13d9:192
exports.encodePacket @ browser.js?9636:123
(anonymous) @ websocket.js?13d9:170
WS.write @ websocket.js?13d9:202
Transport.send @ transport.js?87a5:110
Socket.flush @ socket.js?1006:565
Socket.sendPacket @ socket.js?1006:625
Socket.ping @ socket.js?1006:529
(anonymous) @ socket.js?1006:516
setTimeout (async)
Socket.setPing @ socket.js?1006:514
Socket.onPacket @ socket.js?1006:445
(anonymous) @ socket.js?1006:273
Emitter.emit @ index.js?ea2f:133
Transport.onPacket @ transport.js?87a5:145
Transport.onData @ transport.js?87a5:137
ws.onmessage @ websocket.js?13d9:147

For example, the source websocket.js correlates to 13d9 .

Where does this hex value come from and what is it used for?

I am not concerned with the actual error in this case, I'm just using it for an example.

Answer 1

This is part of your file's URL.

Can't tell for sure what does set it in this case, but it's a common way to avoid caching when updating a js file.

Chrome's console output doesn't expose the column number, so what you have after the : is the line number.

 const script = document.createElement('script'); const blob = new Blob([`const foo = "bar"; // should throw at line 3 throw new TypeError('not a baz');`], {type: "application/javacript"}); script.src = URL.createObjectURL(blob); document.head.appendChild(script); 

Results in

Uncaught TypeError: not a baz            blob:null/96273a46-9...a3b1-12d1f1f3355c:3
   at 96273a46-9f81-4eed-a3b1-12d1f1f3355c:3

As you can see, only the line number is shown here, even though, the Error.stack message does expose the column number in the form script_url:lineno:colno

 const script = document.createElement('script'); const blob = new Blob([`console.log(new Error('foo').stack);`], {type: "application/javacript"}); script.src = URL.createObjectURL(blob); document.head.appendChild(script); /* Error: foo at blob:null/[random-blob-url]:1:13 */