Rolster Rollup

Shared Rollup configuration builder for Rolster TypeScript packages. It standardizes the build pipeline across every @rolster/* project, producing CommonJS, ESM and type declarations from a single, small config file.

Installation

npm i @rolster/rollup -D

Rollup and the @rollup/plugin-* plugins it needs (commonjs, node-resolve, typescript) are already bundled as dependencies, so you don't have to install them yourself. The package also exposes the rolster-rollup command, which runs the bundled Rollup CLI, so consumer projects never need to depend on rollup directly. In the consumer project you only need typescript (to run tsc) and, for the recommended clean script, rimraf.

How it works

The package exports a single function, rolster(options), that returns an array of Rollup configurations. A Rolster build runs in two steps:

1. tsc compiles src/**/*.ts into dist/esm/ (JavaScript + .d.ts).
2. rolster-rollup takes each dist/esm/<entry>.js and bundles it into dist/cjs/<entry>.cjs and — when requiredEsm is enabled — dist/es/<entry>.mjs.

Using it in a project

Four pieces wire a package into this pipeline.

1. rollup.config.mjs

import rolster from '@rolster/rollup';

export default rolster({
  entryFiles: ['index'],
  requiredEsm: true,
  packages: ['@rolster/i18n'] // external deps: not bundled, kept as `external`
});

2. Build scripts in package.json

{
  "scripts": {
    "clean": "rimraf ./dist",
    "build": "npm run clean && tsc -p tsconfig.app.json && rolster-rollup",
    "prepublishOnly": "npm run build"
  }
}

rolster-rollup runs the Rollup CLI bundled with this package using rollup.config.mjs from the current directory. Any extra flag is forwarded to Rollup (for example rolster-rollup --watch), and passing your own -c replaces the default config file.

3. tsconfig.app.json

The build compiles with a dedicated tsconfig that emits only the library source (excluding specs):

{
  "extends": "./tsconfig.json",
  "files": ["node_modules/@rolster/types/index.d.ts"],
  "include": ["src/**/*.ts"],
  "exclude": ["src/**/*.spec.ts"]
}

4. Entry points in package.json

Point the published fields at the generated output:

{
  "types": "./dist/esm/index.d.ts",
  "main": "./dist/cjs/index.cjs",
  "module": "./dist/es/index.mjs",
  "exports": {
    ".": {
      "types": "./dist/esm/index.d.ts",
      "node": {
        "require": "./dist/cjs/index.cjs",
        "import": "./dist/es/index.mjs"
      },
      "default": "./dist/es/index.mjs"
    }
  }
}

API — rolster(options)

| Option | Type | Default | Description | | ---------------------------- | ----------------------------------- | ------------ | ---------------------------------------------------------------------------------------------------------- | | entryFiles | string[] | required | Entry names (without extension). Each is read from <path>/esm/<entry>.js and produces one Rollup config. | | requiredEsm | boolean | false | When true, also emits an ESM bundle at <path>/es/<entry>.mjs (besides the CJS one). | | packages | string[] | [] | Packages marked as external (not bundled) — e.g. other @rolster/* dependencies. | | path | string | 'dist' | Base folder for both input and output. | | plugins | Plugin[] | [] | Extra Rollup plugins appended after the Rolster defaults. | | pluginsOptions.nodeResolve | RollupNodeResolveOptions | — | Options forwarded to @rollup/plugin-node-resolve. | | pluginsOptions.typescript | Partial<RolsterTypescriptOptions> | see below | Overrides for @rollup/plugin-typescript. |

Returns: RollupOptions[] — one configuration per entry in entryFiles.

TypeScript plugin defaults

Each config applies these defaults (override via pluginsOptions.typescript):

{
  tsconfig: './tsconfig.app.json',
  declaration: true,
  declarationDir: 'dist',
  include: ['node_modules/@rolster/types/index.d.ts']
}

Generated output (per entry)

• CJS: <path>/cjs/<entry>.cjs
• ESM (only if requiredEsm: true): <path>/es/<entry>.mjs

Both are emitted with source maps and inlineDynamicImports.

Example: a package with an external dependency

import rolster from '@rolster/rollup';

// @rolster/dates depends on @rolster/i18n, which must stay external
export default rolster({
  entryFiles: ['index'],
  requiredEsm: true,
  packages: ['@rolster/i18n']
});

Contributing

• Daniel Andrés Castillo Pedroza :rocket: