How do you preserve color output from other commands?

[pajtai]

Greater logger! I have a question:

I'm piping to the pino cli to parse and colorize Pino logs, but I sometimes have other output that comes with colors, and the pino cli removes these colors.

For example, I use eslint - which has colored output - how can I preserve that?

Example command nodemon index.js --exec 'npm run lint && node' | pino

[davidmarkclements]

By the time it reaches the prettifier (pino) there is no color.

Try the following: nodemon index.js --exec 'npm run lint && node' | cat

You should see that there's no color, because generally CLI tools that output color will check process.stdout.isTTY (or require('tty').isatty()) and then output the additional terminal codes (or not).

node -p process.stdout.isTTY -> true node -p process.stdout.isTTY | cat -> undefined

[davidmarkclements]

Closing for now, but if you want to keep color through a pipe that's down to configuring which ever libs are outputting colour (if they have that option)

[pajtai]

@davidmarkclements Thanks for that info.

And sure enough, eslint has a --color option that forces color even if isTTY is falsey.

I'll add my config here to preserve eslint colors through a pipe for anyone else who might find it helpful:

  "scripts": {
    "dev": "nodemon index.js --exec 'npm run lint && node' | pino",
    "lint": "eslint --color ."
  },

[github-actions[bot]]

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