@rushstack/stream-collator

This library enables a tool to display live console output from multiple concurrent processes, while ensuring that their output does not get jumbled together.

How does it work?

The stream-collator manages the output of these streams, ensuring that no two streams are writing to the console at the same time. At any given time, one stream registered with the collator is the active stream, which means that particular stream will be live streaming, while the others will wait for that stream to finish before their output is displayed.

For example, if you have 3 streams (e.g. from using child_process.spawn()).

Stream A will write: AAAAA

Stream B will write: BBBBBBBBBBBBBBBBBBBB

Stream C will write: CCCCCCCCCC

If these streams are all being piped directly to stdout (without @rushstack/stream-collator), you could end up with jumbled output:

ABACCCBCCCCBBABBCBBABBBBBBCCAB

Something like the following would be much more useful to users of your application:

AAAAABBBBBBBBBBBBBBBCCCCCCCCCC

This is where the @rushstack/stream-collator comes in!

The active stream

At any given time, a single stream is designated as the active stream. The output of the active stream will always be live-streamed. This is particularly useful for long-running streams. When the active stream finishes, a new stream is selected as the active stream and all of its contents up to that point will be emitted. Whenever an active stream finishes, all background streams which have been completed will be emitted.

Usage

🚨 This is an early preview release. Please report issues! 🚨

WITH VERSION 4.X, THIS PACKAGE HAS BEEN REDESIGNED TO USE THE NEW @rushstack/terminal SYSTEM. IN THE NEXT RELEASE, THE CollatedTerminal API WILL BE REPLACED WITH THE Terminal API.

The usage instructions will be updated once that refactoring is complete.

@rushstack/stream-collator