Create @mediabunny/mp3-encoder, restructure and extend build system

scripts/esbuild/inlined-workers.ts

@@ -0,0 +1,98 @@
+// Adapted from https://github.com/mitschabaude/esbuild-plugin-inline-worker
+
+import * as esbuild from 'esbuild';
+import findCacheDir from 'find-cache-dir';
+import fs from 'node:fs';
+import path from 'node:path';
+
+export function inlineWorkerPlugin(extraConfig: esbuild.BuildOptions): esbuild.Plugin {
+	return {
+		name: 'esbuild-plugin-inline-worker',
+
+		setup(build) {
+			build.onLoad(
+				{ filter: /\.worker\.(js|jsx|ts|tsx)$/ },
+				async ({ path: workerPath }) => {
+					const workerCode = await buildWorker(workerPath, extraConfig);
+					return {
+						contents: `import inlineWorker from '__inline-worker'
+export default function Worker() {
+  return inlineWorker(${JSON.stringify(workerCode)});
+}
+`,
+						loader: 'js',
+					};
+				},
+			);
+
+			const inlineWorkerFunctionCode = `
+export default async function inlineWorker(scriptText) {
+	if (typeof Worker !== 'undefined' && typeof Bun === 'undefined') {
+		// Browser, Deno
+
+		const blob = new Blob([scriptText], { type: "text/javascript" });
+		const url = URL.createObjectURL(blob);
+		const worker = new Worker(url, { type: typeof Deno !== 'undefined' ? 'module' : undefined }); // module for Deno
+		URL.revokeObjectURL(url);
+		return worker;
+	} else {
+		// Node, Bun (Bun's Worker is flaky, worker_threads works much better)
+
+		let Worker;
+		try {
+		Worker = (await import('worker_threads')).Worker;
+		} catch {
+		const workerModule = 'worker_threads';
+		Worker = require(workerModule).Worker;
+		}
+		
+		const worker = new Worker(scriptText, { eval: true });
+		
+		return worker;
+	}
+}
+`;
+
+			build.onResolve({ filter: /^__inline-worker$/ }, ({ path }) => {
+				return { path, namespace: 'inline-worker' };
+			});
+			build.onLoad({ filter: /.*/, namespace: 'inline-worker' }, () => {
+				return { contents: inlineWorkerFunctionCode, loader: 'js' };
+			});
+		},
+	};
+}
+
+const cacheDir = findCacheDir({
+	name: 'esbuild-plugin-inline-worker',
+	create: true,
+});
+if (cacheDir === undefined) {
+	throw new Error('Cache directory not found.');
+}
+
+async function buildWorker(workerPath: string, extraConfig: esbuild.BuildOptions) {
+	const scriptNameParts = path.basename(workerPath).split('.');
+	scriptNameParts.pop();
+	scriptNameParts.push('js');
+	const scriptName = scriptNameParts.join('.');
+	const bundlePath = path.resolve(cacheDir!, scriptName);
+
+	if (extraConfig) {
+		delete extraConfig.entryPoints;
+		delete extraConfig.outfile;
+		delete extraConfig.outdir;
+	}
+
+	await esbuild.build({
+		entryPoints: [workerPath],
+		bundle: true,
+		minify: true,
+		outfile: bundlePath,
+		target: 'es2017',
+		format: 'esm',
+		...extraConfig,
+	});
+
+	return fs.promises.readFile(bundlePath, { encoding: 'utf-8' });
+}