Prefix ([0] [1]) randomly missing

[danbord]

Description:
I'm usign concurrently for my azure fucntions node.js project. I need to compile my typescript and run the azure functions at the same time.

here is my package.json script
"start": "concurrently --kill-others \"tsc -w\" \"func start\"",

Problem is that randomly the prefix is missing from the logs. Which misalign my data in the logs which can be pretty annoying sometimes:

I tried to remove the prefix (since I don't really need it) but setting it to an empty string brings back the [0] and [1]. I also tried setting it to a radom caracter like "-" but still have the same issue

Expected Behavior:

1. Do not skip some prefix
2. Be able to remove the prefix by setting it to empty string

Environment
Node.js v18.19

[gustavohenke]

Thanks for the report.
I'm pretty sure that your command must be writing multiple lines without a line break at the end, e.g. process.stdout.write('hello\nworld').

How this has been a bug for so long is beyond me 🤦
https://github.com/open-cli-tools/concurrently/blame/v8.2.2/src/logger.ts#L238-L239