prefix-cli
What?
Mechanism for prefixing output from multiplexed cli applications
Why?
If you have, for example, a repository hosting a client and api applications,
perhaps you'd like to use npm-run-all
, particularly run-p
to start up
all parts of the system, running in parallel. In this case, it gets a little
difficult to discern which output is coming from where. To solve this ambiguity,
it would be nice if lines from each process' output were prefixed with something
easily recognisable. Enter pre
Usage
some-process | pre {label} {color}
where
-
label
is any text you'd like to prefix lines with -
color
is any color understood by chalk-
color
is optional and will default to white
-
Example please?
prefix-cli
installs a cli application, called pre
, which will echo any input
it receives on stdin with the provided prefix, optionally colored with the provided
color. For example, we may have started with a scripts section like this in our
package.json:
{
"scripts": {
"start-server": "cd server && npm start",
"start-client": "cd client && npm start"
}
}
so we install npm-run-all
so that we can launch both commands with one script:
{
"scripts": {
"start-server": "cd server && npm start",
"start-client": "cd client && npm start",
"start": "run-p start-server start-client"
},
"devDependencies": {
"npm-run-all": "^4.1.5"
}
}
and now our two commands are started simultaneously, with their outputs multiplexed
on the terminal. To disambiguate their outputs, we could install and use prefix-cli
:
"scripts": {
"start-server": "cd server && npm start | pre server yellow",
"start-client": "cd client && npm start | pre client green",
"start": "run-p start-server start-client"
},
"devDependencies": {
"npm-run-all": "^4.1.5",
"prefix-cli": "^1.0.0"
}
and then we would see lines like:
server > setting up routes client > packing stuff... server > listening on port 5000 client > listening on port 3000
This works on the big three platforms (and most likely on others too)