rollup.config.mjs

// @ts-check

import terser from '@rollup/plugin-terser';
import typescript2 from 'rollup-plugin-typescript2';
import packageJSON from './package.json' assert { type: 'json' };

/**
 * Comment with library information to be appended in the generated bundles.
 */
const banner = `/*!
 * ${packageJSON.name} v${packageJSON.version}
 * (c) ${packageJSON.author.name}
 * Released under the ${packageJSON.license} License.
 */
`;

/**
 * Creates an output options object for Rollup.js.
 * @param {import('rollup').OutputOptions} options
 * @returns {import('rollup').OutputOptions}
 */
function createOutputOptions(options) {
    return {
        banner,
        name: '[libraryCamelCaseName]',
        exports: 'named',
        sourcemap: true,
        ...options,
    };
}

/**
 * @type {import('rollup').RollupOptions}
 */
const options = {
    input: './src/index.ts',
    output: [
        createOutputOptions({
            file: './dist/index.js',
            format: 'commonjs',
        }),
        createOutputOptions({
            file: './dist/index.cjs',
            format: 'commonjs',
        }),
        createOutputOptions({
            file: './dist/index.mjs',
            format: 'esm',
        }),
        createOutputOptions({
            file: './dist/index.esm.js',
            format: 'esm',
        }),
        createOutputOptions({
            file: './dist/index.umd.js',
            format: 'umd',
        }),
        createOutputOptions({
            file: './dist/index.umd.min.js',
            format: 'umd',
            plugins: [terser()],
        }),
    ],
    plugins: [
        typescript2({
            clean: true,
            useTsconfigDeclarationDir: true,
            tsconfig: './tsconfig.bundle.json',
        }),
    ],
};

export default options;