How to pass env variable to rollup.config.js via npm cli?

Question

I have a scripts folder in which many individual scripts inside seperate folder, I would like to build each separately via passing the script name as parameter.

I have set up rollup in package.json like "watch": "rollup --watch --config rollup.config.js"

I would like to pass parameter from cli like npm run watch script_name=abc_script

It can be accessible in rollup.config.js via process.argv

But getting this error

rollup v1.23.1 bundles abc_script → dist/bundle.js [!] Error: Could not resolve entry module

Everything seems fine without npm cli parameter.

Rollup have --environment variable but it's bit long to use npm run watch -- --environment script:script_name

Is there any way to shorten this?

Thanks in advance.

Answer 1

Alternatively, you can pass environment variables to the command - it's much easier to process than command-line arguments.

Cli usage:

minify=on ./node_modules/.bin/rollup -c

package.json script:

{
  ...
  scripts: {
    ...
    "build-production": "minify=on rollup -c"
  }
}

rollup.config.js

const enableMinification = process.env.minify === 'on'

Answer 2

You can pass arguments which will be caught by process.argv like this

npm run watch -- some_arg

In your program, you will get an array in process.argv in this the last value will be the value passed to the program.