console.error unexpectedly turns output red

[Jason3S]

Related to PR #51629

I'm a bit surprised that this landed without a link to the discussion. #40361 is a feature request, but doesn't have a real discussion around the pros/cons and how it will impact the nodejs ecosystem.

I would have rather seen color added to the formatting of Errors instead of blanket red/yellow for console.error/console.warn.

I realize that in some way, this PR makes the behavior closer to that in the browser, but browsers do not have CLI applications.

I treat console.log and console.error as separate channels. Traditionally stdout is used for output of the program. It contains the result to be used, think grep. stderr is used for diagnostics, status, and messages to the user while the application is running. Color is not implied.

I would rather that this PR implemented color as a opt in vs trying to figure out how to opt out.

Originally posted by @Jason3S in #51629 (comment)

[avivkeller]

FWIW I'm +1 on the idea of making the coloring of console opt-in, but that's not my say. (Or just removing it entirely, and having the users handle it themselves)

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CC @nodejs/console

[avivkeller]

Related to #51503
Related to #51629
Related to #40361
Related to #53665

[jasnell]

I'm +1 on making the colorization opt-in

[ruyadorno]

I'm -1 on making colorization opt-in.

Color has been opt-out in the runtime for as long as I can remember and I would need a much stronger argument to be convinced otherwise.

Although I don't necessarily agree with the current state of things, the console APIs are properly documented as debugging only: https://nodejs.org/docs/latest/api/console.html#console - and as such their output is not meant to be stable. With that in mind, I would advise cli apps that need stable formatting for their output to write to process.stdout and process.stderr instead of relying on console.log and console.error.

[MoLow]

-1 as well. maybe we can find another mitigation.
also, coloring is not new for console log since logged items are passed to util.inspect wich adds colors in various cases

[joyeecheung]

Shouldn't the color only be default when the stdout/stderr are TTY? I wonder #53665 is more of a bug of the TTY detection not smart enough

[marco-ippolito]

+1 on making the color opt-in, expect tty maybe

[ruyadorno]

Shouldn't the color only be default when the stdout/stderr are TTY? I wonder #53665 is more of a bug of the TTY detection not smart enough

I remember testing TTY detection and it was working as expected.

[cjihrig]

From what I can tell, the TTY detection is working as expected.

[jakebailey]

Docs or not, I do think console.error's preexisting behavior was expected by most people and is widely used as a canonical way to "print to stderr". I've seen quite a few projects mentioning breakage due to this change who are hoping for it to be reverted. I have personally written code which assumed that console.log would go to stdout such that that info can be piped, while console.error did not and was treated as plain logging.

[avivkeller]

FWIW The way I see it, there are few different choices here, such as:

1. Do nothing
2. Revert console: colorize console error and warn #51629
3. Make the special colors opt-in
4. Make the special colors opt-out

[jasnell]

What major versions implement the updated colorization? As a compromise here, I'd suggest that we make sure the change is not backported to anything before 22 if it has been already and we retroactively mark it a semver-major change. Keep the new behavior moving forward with the additional documentation,

[avivkeller]

What major versions implement the updated colorization?

v20.15.0 (794e450) and v22.2.0 (db76c58)