Node 22 doesn't honor the --watch-preserve-output command-line parameter

[claudioc]

Version

22.12.0

Platform

macOS 14.7.2

Subsystem

No response

What steps will reproduce the bug?

I have this command that I run with npm: node --env-file=.env --watch-preserve-output --watch-path ./dist/server and it has always worked as expected. Now, after switching (using nvm) to node 22, the screen is always cleared upon restarting. If I switch back to node 20 (with nvm), the --watch-preserve-output parameter is honored.

How often does it reproduce? Is there a required condition?

It happens all the times

What is the expected behavior? Why is that the expected behavior?

This is apparently a regression on the node 20 line.

What do you see instead?

The screen is cleared upon restarting the server

Additional information

No response

[abdullahshahid95]

You can run this command in following way, it runs identically in both node 20 and 22.
node --env-file=.env --watch --watch-preserve-output ./dist/server

[claudioc]

@abdullahshahid95 my full script line is the following. Your line doesn't contain the script to run

"dev:start": "wait-on ./dist/server/app.js && node --env-file=.env --watch-preserve-output --watch-path ./dist/server ./dist/server/app.js",

[abdullahshahid95]

@claudioc As per the example in https://nodejs.org/api/cli.html#--watch-preserve-output, --watch-preserve-output is used with --watch. If you add --watch before --watch-preserve-output, it may preserve previous logs. I have added it below.
"dev:start": "wait-on ./dist/server/app.js && node --env-file=.env --watch --watch-preserve-output --watch-path ./dist/server ./dist/server/app.js"

[claudioc]

@abdullahshahid95 OK, adding the --watch flag works again. You are pointing to the documentation, but the documentation is confusing at least:

--watch-path "Starts Node.js in watch mode and specifies what paths to watch."

So why the --watch is ALSO needed to have the -watch-preserve-output work as expected!? Something is a bit unclear: according to the doc you should not need to add --watch to have -watch-preserve-output

[abdullahshahid95]

@claudioc Yes, it's definitely confusing :-)
I tried few combinations and found out, --watch watches main file and imported files. --watch-path only watches files in specific paths.
--watch-preserve-output works only with --watch and preserves previous output.
Screenshot of documentation below.