rollup.config.js

import fs from 'fs';
import path from 'path';
import alias from 'rollup-plugin-alias';
import commonjs from 'rollup-plugin-commonjs';
import json from 'rollup-plugin-json';
import resolve from 'rollup-plugin-node-resolve';
import { string } from 'rollup-plugin-string';
import { terser } from 'rollup-plugin-terser';
import typescript from 'rollup-plugin-typescript';
import pkg from './package.json';

const commitHash = (function() {
	try {
		return fs.readFileSync('.commithash', 'utf-8');
	} catch (err) {
		return 'unknown';
	}
})();

const now = new Date(
	process.env.SOURCE_DATE_EPOCH ? process.env.SOURCE_DATE_EPOCH * 1000 : new Date().getTime()
).toUTCString();

const banner = `/*
  @license
	Rollup.js v${pkg.version}
	${now} - commit ${commitHash}

	https://github.com/rollup/rollup

	Released under the MIT License.
*/`;

const onwarn = warning => {
	// eslint-disable-next-line no-console
	console.error(
		'Building Rollup produced warnings that need to be resolved. ' +
			'Please keep in mind that the browser build may never have external dependencies!'
	);
	throw new Error(warning.message);
};

const expectedAcornImport = "import acorn__default, { tokTypes, Parser as Parser$1 } from 'acorn';";
const newAcornImport =
	"import * as acorn__default from 'acorn';\nimport { tokTypes, Parser as Parser$1 } from 'acorn';";

// by default, rollup-plugin-commonjs will translate require statements as default imports
// which can cause issues for secondary tools that use the ESM version of acorn
function fixAcornEsmImport() {
	return {
		name: 'fix-acorn-esm-import',
		renderChunk(code, chunk, options) {
			if (/esm?/.test(options.format)) {
				let found = false;
				const fixedCode = code.replace(expectedAcornImport, () => {
					found = true;
					return newAcornImport;
				});
				if (!found) {
					this.error(
						'Could not find expected acorn import, please deactive this plugin and examine generated code.'
					);
				}
				return fixedCode;
			}
		}
	};
}

const moduleAliases = {
	resolve: ['.js', '.json', '.md'],
	'acorn-dynamic-import': path.resolve('node_modules/acorn-dynamic-import/src/index.js'),
	'help.md': path.resolve('bin/src/help.md'),
	'package.json': path.resolve('package.json')
};

export default command => {
	const nodeBuilds = [
		/* Rollup core node builds */
		{
			input: 'src/node-entry.ts',
			onwarn,
			plugins: [
				alias(moduleAliases),
				resolve(),
				json(),
				commonjs({ include: 'node_modules/**', namedExports: { micromatch: ['matcher'] } }),
				typescript({include: '**/*.{ts,js}'}),
				fixAcornEsmImport()
			],
			// acorn needs to be external as some plugins rely on a shared acorn instance
			external: ['fs', 'path', 'events', 'module', 'util', 'crypto', 'acorn', 'tty', 'net', 'url'],
			treeshake: {
				moduleSideEffects: false,
				propertyReadSideEffects: false
			},
			output: [
				{ file: 'dist/rollup.js', format: 'cjs', sourcemap: true, banner },
				{ file: 'dist/rollup.es.js', format: 'esm', banner }
			]
		},
		/* Rollup CLI */
		{
			input: 'bin/src/index.ts',
			onwarn,
			plugins: [
				alias(moduleAliases),
				resolve(),
				json(),
				string({ include: '**/*.md' }),
				commonjs({ include: 'node_modules/**' }),
				typescript({include: '**/*.{ts,js}'}),
			],
			external: ['fs', 'path', 'module', 'events', 'rollup', 'assert', 'os', 'util'],
			treeshake: {
				moduleSideEffects: false,
				propertyReadSideEffects: false
			},
			output: {
				file: 'bin/rollup',
				format: 'cjs',
				banner: '#!/usr/bin/env node',
				paths: {
					rollup: '../dist/rollup.js'
				}
			}
		}
	];

	if (command.configNoBrowser) {
		return nodeBuilds;
	}
	return nodeBuilds.concat([
		/* Rollup core browser builds */
		{
			input: 'src/browser-entry.ts',
			onwarn,
			plugins: [
				alias(moduleAliases),
				resolve({ browser: true }),
				json(),
				{
					load: id => {
						if (~id.indexOf('fs.ts')) return fs.readFileSync('browser/fs.ts', 'utf-8');
						if (~id.indexOf('path.ts')) return fs.readFileSync('browser/path.ts', 'utf-8');
					}
				},
				commonjs(),
				typescript({include: '**/*.{ts,js}'}),
				terser({ module: true, output: { comments: 'some' } })
			],
			treeshake: {
				moduleSideEffects: false,
				propertyReadSideEffects: false
			},
			output: [
				{ file: 'dist/rollup.browser.js', format: 'umd', name: 'rollup', banner },
				{ file: 'dist/rollup.browser.es.js', format: 'esm', banner }
			]
		}
	]);
};