Custom reporter support

[mongolyy]

Overview

I would like Biome to support user-defined custom reporters.

Background / Motivation

• I use reviewdog. Reviewdog requires diagnostic messages to be formatted in its own RDFormat. Currently, Biome does not provide a way to extend or override the output format easily.
• ESLint offers the ability to specify a custom format via its -f / --format option. Users who have leveraged custom formatters in ESLint would also benefit from a similar feature in Biome.

[ematipico]

Biome already has different different reporters: https://biomejs.dev/reference/reporters/

--reporter=<json|json-pretty|github|junit|summary|gitlab>

[mongolyy]

Thank you for your response.

I know there are multiple reporters available, but I’d like to define my own output format for the reporter.

Specifically, I want to output a custom format called “RDFormat” for the tool I’m using.
Something like this, for example: --reporter=my-customize.js

[dyc3]

As a workaround, you could use the json reporter and write a script to convert that to RDFormat. If there's something missing from the json reporter that you need, we would definitely want to address that.

[ematipico]

Yeah, we could add a new reporter :) for rdjson

[weyert]

I wish you could run multiple reporters at the same time. I would like to have github and junit. No I have to run it them separately. Currently, I am using a script like below to achieve it. Also it appears you can't write the output to disk and need to manage it yourself.

# Check if running in GitHub Actions
if [ "$GITHUB_ACTIONS" = "true" ]; then
    # Generate junit report only in CI
   mkdir -p coverage
    biome lint --reporter=junit > coverage/junit.xml
    
    # Output Github Actions format
    biome lint --reporter=github
else
    # Regular lint command for local development
    biome lint
fi

[arendjr]

@weyert why would you use a script at all for local development if all it does is call biome lint? You could also add it to package.json if you like, so people only need to do yarn/pnpm lint or npm run lint.

Then the only thing that remains for CI are the commands:

mkdir -p coverage
biome lint --reporter=junit > coverage/junit.xml
biome lint --reporter=github

To be frank that seems like a perfectly reasonable CI configuration to me.