rollup custom cli arguments for the config throwing errors

Question

I have an app in progress which requires 3 micro code bases and some iframe postMessage stuff.

Controlling the build of all these i aim to manage from a single rollup config file and injecting arguments in via cli:

  "scripts": {
    "dev:child": "rollup -c rollup.config.js -w --for_type child",
    "dev:parent": "rollup -c rollup.config.js -w --for_type parent",
    "dev:sidebar": "rollup -c rollup.config.js -w --for_type sidebar",

My rollup config works but the issue is that rollup complains that for_type is a non recognised argument.

What is the proper way of injecting custom arguments to rollup?

I cannot see anything here: https://rollupjs.org/guide/en/#configuration-files

Answer 1

When you export a function instead of an object in rollup.config.js, the first argument of the function will be a CLI arguments object. For example, if you config is:

export default cliArgs => {
    let build = {
        input: 'src/index.js',
        output: [/* ... */],/
        plugins: [/* ... */]
    };

    switch (cliArgs.for_type) {
        case 'child':
            // Customise build for child
            break;
        case 'parent':
            // Customise build for parent
            break;
        case 'sidebar':
            // Customise build for sidebar
            break;
        default:
            // No CLI argument
            break;
    }

    return build
};

Have another look at the documentation for more info.

Answer 2

From https://rollupjs.org/guide/en/#configuration-files

You can even define your own command line options if you prefix them with config:

export default commandLineArgs => {
  if (commandLineArgs.configDebug === true) {
    return debugConfig;
  }
  return defaultConfig;
};