vite.config.js

import { defineConfig } from 'vite';
import reactRefresh from '@vitejs/plugin-react-refresh';
import * as esbuild from 'esbuild';
import path from 'path';
import pkg from './package.json';

/**
 * Bundles vite worker modules during development into single scripts.
 * see: https://github.com/hms-dbmi/viv/pull/469#issuecomment-877276110
 * @returns {import('vite').Plugin}
 */
const bundleWebWorker = {
    name: 'bundle-web-worker',
    apply: 'serve', // plugin only applied with dev-server
    async transform(_, id) {
        if (/\?worker_file$/.test(id)) {
            // just use esbuild to bundle the worker dependencies
            const bundle = await esbuild.build({
                entryPoints: [id],
                inject: ['./src/alias/buffer-shim.js'],
                format: 'iife',
                bundle: true,
                write: false
            });
            if (bundle.outputFiles.length !== 1) {
                throw new Error('Worker must be a single module.');
            }
            return bundle.outputFiles[0].text;
        }
    }
};

// We can't inject a global `Buffer` polyfill for the worker entrypoint using vite alone,
// so we reuse the `bundle-web-worker` plugin to inject the buffer shim during production.
const manualInlineWorker = {
    apply: 'build',
    async transform(code, id) {
        if (id.endsWith('bam-worker.ts?worker&inline') || id.endsWith('vcf-worker.ts?worker&inline')) {
            const bundle = await bundleWebWorker.transform(code, id + '?worker_file');
            const base64 = Buffer.from(bundle).toString('base64');
            // https://github.com/vitejs/vite/blob/72cb33e947e7aa72d27ed0c5eacb2457d523dfbf/packages/vite/src/node/plugins/worker.ts#L78-L87
            return `const encodedJs = "${base64}";
const blob = typeof window !== "undefined" && window.Blob && new Blob([atob(encodedJs)], { type: "text/javascript;charset=utf-8" });
export default function() {
  const objURL = blob && (window.URL || window.webkitURL).createObjectURL(blob);
  try {
    return objURL ? new Worker(objURL) : new Worker("data:application/javascript;base64," + encodedJs, {type: "module"});
  } finally {
    objURL && (window.URL || window.webkitURL).revokeObjectURL(objURL);
  }
}`;
        }
    }
};

const alias = {
    'gosling.js': path.resolve(__dirname, './src/index.ts'),
    '@gosling-lang/gosling-schema': path.resolve(__dirname, './src/gosling-schema/index.ts'),
    '@gosling-lang/higlass-schema': path.resolve(__dirname, './src/higlass-schema/index.ts'),
    "@gosling-lang/gosling-track": path.resolve(__dirname, "./src/tracks/gosling-track/index.ts"),
    "@gosling-lang/gosling-genomic-axis": path.resolve(__dirname, "./src/tracks/gosling-genomic-axis/index.ts"),
    "@gosling-lang/gosling-brush": path.resolve(__dirname, "./src/tracks/gosling-brush/index.ts"),
    "@gosling-lang/dummy-track": path.resolve(__dirname, "./src/tracks/dummy-track/index.ts"),
    "@data-fetchers": path.resolve(__dirname, "./src/data-fetchers/index.ts"),
    zlib: path.resolve(__dirname, './src/alias/zlib.ts'),
    uuid: path.resolve(__dirname, './node_modules/uuid/dist/esm-browser/index.js'),
    stream: path.resolve(__dirname, './node_modules/stream-browserify')
};

const skipExt = new Set(['@gmod/bbi', 'uuid']);
const external = [...Object.keys(pkg.dependencies), ...Object.keys(pkg.peerDependencies)].filter(
    dep => !skipExt.has(dep)
);

const esm = defineConfig({
    build: {
        emptyOutDir: false,
        outDir: 'dist',
        minify: false,
        target: 'es2018',
        sourcemap: true,
        lib: {
            entry: path.resolve(__dirname, 'src/index.ts'),
            formats: ['es'],
            fileName: 'gosling'
        },
        rollupOptions: { external }
    },
    resolve: { alias },
    plugins: [manualInlineWorker]
});

const dev = defineConfig({
    build: { outDir: 'build' },
    resolve: { alias },
    define: {
        'process.platform': 'undefined',
        'process.env.THREADS_WORKER_INIT_TIMEOUT': 'undefined'
    },
    plugins: [bundleWebWorker, manualInlineWorker]
});

const testing = defineConfig({
    resolve: { alias },
    test: {
        globals: true,
        setupFiles: [path.resolve(__dirname, './scripts/setup-vitest.js')],
        environment: 'jsdom',
        threads: false,
        environmentOptions: {
            jsdom: {
                resources: 'usable'
            }
        },
        coverage: {
          reportsDirectory: './coverage',
          reporter: ['lcov', 'text'],
          include: ['src', 'editor'],
        }
    }
});

export default ({ command, mode }) => {
    if (command === 'build' && mode === 'lib') return esm;
    if (mode == 'test') return testing;
    if (mode === 'editor') {
        dev.plugins.push(reactRefresh());
    }
    return dev;
};