async build()

in packages/metro/src/Server.js [170:249]
77 lines of code
4 McCabe index (conditional complexity)

  async build(options: BundleOptions): Promise<{
    code: string,
    map: string,
    ...
  }> {
    const {
      entryFile,
      graphOptions,
      onProgress,
      serializerOptions,
      transformOptions,
    } = splitBundleOptions(options);

    const {prepend, graph} = await this._bundler.buildGraph(
      entryFile,
      transformOptions,
      {
        onProgress,
        shallow: graphOptions.shallow,
      },
    );

    const entryPoint = this._getEntryPointAbsolutePath(entryFile);

    const bundleOptions = {
      asyncRequireModulePath: await this._resolveRelativePath(
        this._config.transformer.asyncRequireModulePath,
        {transformOptions, relativeTo: 'project'},
      ),
      processModuleFilter: this._config.serializer.processModuleFilter,
      createModuleId: this._createModuleId,
      getRunModuleStatement: this._config.serializer.getRunModuleStatement,
      dev: transformOptions.dev,
      projectRoot: this._config.projectRoot,
      modulesOnly: serializerOptions.modulesOnly,
      runBeforeMainModule:
        this._config.serializer.getModulesRunBeforeMainModule(
          path.relative(this._config.projectRoot, entryPoint),
        ),
      runModule: serializerOptions.runModule,
      sourceMapUrl: serializerOptions.sourceMapUrl,
      sourceUrl: serializerOptions.sourceUrl,
      inlineSourceMap: serializerOptions.inlineSourceMap,
      serverRoot:
        this._config.server.unstable_serverRoot ?? this._config.projectRoot,
    };
    let bundleCode = null;
    let bundleMap = null;
    if (this._config.serializer.customSerializer) {
      const bundle = await this._config.serializer.customSerializer(
        entryPoint,
        prepend,
        graph,
        bundleOptions,
      );
      if (typeof bundle === 'string') {
        bundleCode = bundle;
      } else {
        bundleCode = bundle.code;
        bundleMap = bundle.map;
      }
    } else {
      bundleCode = bundleToString(
        baseJSBundle(entryPoint, prepend, graph, bundleOptions),
      ).code;
    }
    if (!bundleMap) {
      bundleMap = sourceMapString(
        [...prepend, ...this._getSortedModules(graph)],
        {
          excludeSource: serializerOptions.excludeSource,
          processModuleFilter: this._config.serializer.processModuleFilter,
        },
      );
    }
    return {
      code: bundleCode,
      map: bundleMap,
    };
  }