rollup.config.mjs

import fs from 'fs';
import { execSync } from 'child_process';

import babel from '@rollup/plugin-babel';
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';
import globals from 'rollup-plugin-node-globals';
import builtins from 'rollup-plugin-node-builtins';
import replace from '@rollup/plugin-replace';
import sourcemaps from 'rollup-plugin-sourcemaps2';
import terser from '@rollup/plugin-terser';
import json from '@rollup/plugin-json';
import { importAsString } from 'rollup-plugin-string-import';

import serve from 'rollup-plugin-serve';
import livereload from 'rollup-plugin-livereload';

const ESM = (process.env.ESM !== 'false'); // default to ESM on
const MINIFY = (process.env.MINIFY === 'true');
const SERVE = (process.env.SERVE === 'true');

const outputFile = `dist/tangram.${MINIFY ? 'min' : 'debug'}.${ESM ? 'm' : ''}js`;

// Use two pass code splitting and re-bundling technique, for another example see:
// https://github.com/mapbox/mapbox-gl-js/blob/master/rollup.config.js

const config = [{
    input: ['src/index.js', 'src/scene/scene_worker.js'],
    output: {
        dir: 'build',
        format: 'amd',
        sourcemap: 'inline',
        indent: false,
        chunkFileNames: 'shared.js',
    },
    plugins: [
        resolve({
            browser: true,
            preferBuiltins: false,
        }),
        commonjs({
            // Avoids Webpack minification errors
            ignoreGlobal: true,
        }),
        json(), // load JSON files
        importAsString({
            include: ['**/*.glsl'] // inline shader files
        }),

        babel({
            exclude: 'node_modules/**',
            babelHelpers: "runtime"
        }),

        // These are needed for jszip node-environment compatibility,
        // previously provided by browserify
        globals(),
        builtins(),

        MINIFY ? terser() : false
    ]
}, {
    // Second pass: combine the chunks from the first pass into a single bundle
    input: 'build/bundle.mjs',
    output: {
        name: 'Tangram',
        file: outputFile,
        format: ESM ? 'esm' : 'umd',
        sourcemap: MINIFY ? false : true,
        indent: false,
        // intro: fs.readFileSync(require.resolve('./build/intro.js'), 'utf8')
        intro: `
            // define() gets called for each chunk generated by the first Rollup pass.
            // The order the chunks are called in is controlled by the imports in bundle.js:
            //
            // shared.js: shared dependencies between main and worker threads
            // scene_worker.js: worker thread code
            // index.js: main thread code

            // Once all chunks have been provided, the worker thread code is assembled,
            // incorporating the shared chunk code, then turned into a blob URL which
            // can be used to instantiate the worker.

            var shared, worker, Tangram = {};

            function define(_, chunk) {
                    if (!shared) {
                        shared = chunk;
                    } else if (!worker) {
                        worker = chunk;
                    } else {
                        var worker_bundle = 'var shared_chunk = {}; (' + shared + ')(shared_chunk); (' + worker + ')(shared_chunk);'
                        var shared_chunk = {};
                        shared(shared_chunk);
                        Tangram = chunk(shared_chunk);
                        Tangram.workerURL = window.URL.createObjectURL(new Blob([worker_bundle], { type: 'text/javascript' }));
                    }
            }
        `
    },
    treeshake: false,
    plugins: [
        replace({
            preventAssignment: true,
            values: {
                _ESM: ESM,
                _SHA: '\'' + String(execSync('git rev-parse HEAD')).trim(1) + '\''
            }
        }),
        sourcemaps(), // use source maps produced in the first pass

        // optionally start server and watch for rebuild
        SERVE ? serve({
            port: 8000,
            contentBase: '',
            headers: {
                'Access-Control-Allow-Origin': '*'
            }
        }): false,
        SERVE ? livereload({
            watch: 'dist'
        }) : false
    ],
}];

export default config