esbuild-plugin-inline-worker.mjs

/* eslint-env node */

// copy of https://github.com/mitschabaude/esbuild-plugin-inline-worker
// modified to work with node (using base64 instead of blob)

import esbuild from 'esbuild';
import findCacheDir from 'find-cache-dir';
import fs from 'fs';
import path from 'path';

export {inlineWorkerPlugin as default};

function inlineWorkerPlugin(extraConfig) {
  return {
    name: 'esbuild-plugin-inline-worker',

    setup(build) {
      build.onLoad(
        {filter: /\.worker.(js|jsx|ts|tsx)$/},
        async ({path: workerPath}) => {
          // let workerCode = await fs.promises.readFile(workerPath, {
          //   encoding: 'utf-8',
          // });

          let workerCode = await buildWorker(workerPath, extraConfig);
          return {
            contents: `import inlineWorker from '__inline-worker'
export default function Worker() {
  return inlineWorker(${JSON.stringify(workerCode)});
}
`,
            loader: 'js',
          };
        }
      );

      build.onResolve({filter: /^__inline-worker$/}, ({path}) => {
        return {path, namespace: 'inline-worker'};
      });
      build.onLoad({filter: /.*/, namespace: 'inline-worker'}, () => {
        return {contents: inlineWorkerFunctionCode, loader: 'js'};
      });
    },
  };
}

const inlineWorkerFunctionCode = `
export default function inlineWorker(scriptText) {
  let base64 = btoa(scriptText);
  let url = new URL(\`data:application/javascript;base64,\${base64}\`);
  let worker = new Worker(url);
  return worker;
}
`;

let cacheDir = findCacheDir({
  name: 'esbuild-plugin-inline-worker',
  create: true,
});

async function buildWorker(workerPath, extraConfig) {
  let scriptNameParts = path.basename(workerPath).split('.');
  scriptNameParts.pop();
  scriptNameParts.push('js');
  let scriptName = scriptNameParts.join('.');
  let 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'});
}