Function esbuildCompile

build-system/tasks/helpers.js:259–442

* Transforms a given JavaScript file entry point with esbuild and babel, and * watches it for changes (if required). * * @param {string} srcDir * @param {string} srcFilename * @param {string} destDir * @param {!Object} options * @return {!Promise}

(srcDir, srcFilename, destDir, options)

 * @return {!Promise}
 */
async function esbuildCompile(srcDir, srcFilename, destDir, options) {
  const startTime = Date.now();
  const entryPoint = path.join(srcDir, srcFilename);
  const filename = options.minify
    ? options.minifiedName
    : (options.toName ?? srcFilename);
  // This guards against someone passing `minify: true` but no `minifiedName`.
  if (!filename) {
    throw new Error('No minifiedName provided for ' + srcFilename);
  }
  const destFilename = maybeToEsmName(filename);
  const destFile = path.join(destDir, destFilename);

  if (watchedTargets.has(entryPoint)) {
    return watchedTargets.get(entryPoint).rebuild();
  }

  /**
   * Splits up the wrapper to compute the banner and footer
   * @return {object}
   */
  function splitWrapper() {
    const wrapper = options.wrapper ?? wrappers.none;
    const sentinel = '<%= contents %>';
    const start = wrapper.indexOf(sentinel);
    return {
      banner: {js: wrapper.slice(0, start)},
      footer: {js: wrapper.slice(start + sentinel.length)},
    };
  }
  const {banner, footer} = splitWrapper();
  const config = await getAmpConfigForFile(destFilename, options);
  const compiledFile = await getCompiledFile(srcFilename);
  banner.js = config + banner.js + compiledFile;

  let babelCaller =
    options.babelCaller ?? (options.minify ? 'minified' : 'unminified');

  // We read from the current binary configuration options if it is an
  // no css binary output. (removes CSS installation)
  if (options.ssrCss) {
    babelCaller += '-ssr-css';
  }

  const babelPlugin = getEsbuildBabelPlugin(
    babelCaller,
    /* enableCache */ true,
    {plugins: options.babelPlugins}
  );
  const plugins = [babelPlugin];

  if (options.remapDependencies) {
    const {externalDependencies: externals, remapDependencies: remaps} =
      options;

    plugins.unshift(
      remapDependenciesPlugin({externals, remaps, resolve: ampResolve})
    );