Reuse attached DevTools to re-execute a watched file

[cdoublev]

What is the problem this feature will solve?

When executing a file with node and --watch and --inspect-brk or --inspect-wait to inspect the code in DevTools, NodeJS waits for DevTools to be detached before executing the file again after a modification. The user must therefore close this DevTools window and open a new one that will listen for the new process.

What is the feature you are proposing to solve the problem?

I would like the same DevTools window to be used to attach the new process.

What alternatives have you considered?

None, I would say...

I replaced Jest with node:test in a project and encountered this behavior when trying to inspect a file while running a test.

And that seems possible in Deno: denoland/deno#20660

[juanarbol]

What do you mean? I'm trying to repro your issue, but as the restart spawns a new process, devtools will simply re-attach

[cdoublev]

On my end, the web socket URL changes every time a watched file is saved. So I guess that is why DevTools does not automatically re-attach.

For example, after running node --watch --inspect-brk=0.0.0.0:9222 watch-inspect.js and opening a new tab to chrome://inspect and clicking on inspect to open DevTools, the standard output is:

Debugger listening on ws://0.0.0.0:9222/83de1f16-bbc9-445d-8b4b-7d03032ad051
For help, see: https://nodejs.org/en/docs/inspector
Debugger attached.

If I resume the script execution, the standard output is:

Waiting for the debugger to disconnect...

Then if I change watch-inspect.js, the standard output is:

Restarting 'watch-inspect.js'
Debugger listening on ws://0.0.0.0:9222/5628f002-a303-499d-b1bc-7a25181d665d
For help, see: https://nodejs.org/en/docs/inspector

node --version is 24.12.0. I run it on my machine, not in a container or virtual machine.

If this is a bug on my end, please let me know if I should close this ticket and open a new one.

[juanarbol]

I've faced issues like that before, with apps that holds child processes; do you have anything like that? Stuff that won't let do a proper teardown?

[cdoublev]

Nope. watch-inspect.js is empty. I simply press Ctrl + S to trigger a restart. I forgot to mention that I use Chrome for Linux Version 143.0.7499.169.