rollup.config.js

const fs = require('fs');
const path = require('path');
const { minify } = require('terser');
const { transpileModule } = require('typescript');
const tsconfig = require('./tsconfig.json');
const pkg = require('./package.json');

const resolve = {
	name: 'resolve',
	resolveId(file, importer) {
		let tmp, { ext } = path.parse(file);
		if (ext) return file;

		let next = path.resolve(path.dirname(importer), file);
		if (fs.existsSync(next)) return next;

		if (fs.existsSync(tmp = next + '.ts')) return tmp;
		if (fs.existsSync(tmp = next + '.js')) return tmp;

		return null;
	}
};

const terser = {
	name: 'terser',
	renderChunk(code, _chunk, opts) {
		return minify(code, {
			toplevel: true,
			sourceMap: !!opts.sourcemap,
			compress: true,
		});
	}
};

const typescript = {
	name: 'typescript',
	transform(code, file) {
		if (!/\.ts$/.test(file)) return code;
		// @ts-ignore
		let output = transpileModule(code, { ...tsconfig, fileName: file });
		return {
			code: output.outputText.replace('$$VERSION$$', pkg.version),
			map: output.sourceMapText || null
		};
	}
};

function make(file, format) {
	return {
		file, format,
		freeze: false,
		esModule: false,
		interop: false,
		strict: false,
	};
}

module.exports = {
	input: 'src/index.ts',
	output: [
		make('index.mjs', 'esm'),
		make('index.js', 'cjs'),
	],
	external: [
		...require('module').builtinModules,
		...Object.keys(pkg.dependencies),
	],
	plugins: [
		resolve,
		typescript,
		terser,
	]
}