facebook/react · error · Error

TODO: Implement the server compiler.

Error message

TODO: Implement the server compiler.

What it means

The webpack plugin's constructor accepts isServer as a boolean but only the false path (client reference + manifest compilation) is implemented; passing isServer: true immediately throws 'TODO: Implement the server compiler.' The server side of the RSC pipeline is handled by the node loader/register at runtime, not by this plugin pass.

Source

Thrown at packages/react-server-dom-webpack/src/ReactFlightWebpackPlugin.js:79

  serverConsumerManifestFilename?: string,
};

const PLUGIN_NAME = 'React Server Plugin';

export default class ReactFlightWebpackPlugin {
  clientReferences: $ReadOnlyArray<ClientReferencePath>;
  chunkName: string;
  clientManifestFilename: string;
  serverConsumerManifestFilename: string;

  constructor(options: Options) {
    if (!options || typeof options.isServer !== 'boolean') {
      throw new Error(
        PLUGIN_NAME + ': You must specify the isServer option as a boolean.',
      );
    }
    if (options.isServer) {
      throw new Error('TODO: Implement the server compiler.');
    }
    if (!options.clientReferences) {
      this.clientReferences = [
        {
          directory: '.',
          recursive: true,
          include: /\.(js|ts|jsx|tsx)$/,
        },
      ];
    } else if (
      typeof options.clientReferences === 'string' ||
      !isArray(options.clientReferences)
    ) {
      this.clientReferences = [options.clientReferences as $FlowFixMe];
    } else {
      // $FlowFixMe[incompatible-type] found when upgrading Flow
      this.clientReferences = options.clientReferences;
    }

View on GitHub (pinned to eafeac097b)

Solutions

1. Set isServer: false; the server bundle does not need this plugin
2. Produce the server side via the runtime loader (react-server-dom-webpack/node-loader in module.rules or --loader) plus the generated client manifest
3. Track upstream for server-compiler support instead of working around the throw

Example fix

// before
new ReactFlightWebpackPlugin({isServer: process.env.NODE_ENV !== 'browser', ...})

// after (client webpack config only)
new ReactFlightWebpackPlugin({isServer: false, clientReferences: [...]})
// server bundle: no plugin; add the node loader to module.rules instead

const SUPPORTED = new Set(['isServer:false']);
if (options?.isServer === true) {
  throw new Error('server compiler pass is not implemented; use the node loader for the server bundle');
}

function isSupportedPluginOptions(o) {
  return o == null || o.isServer !== true; // only the client pass exists
}

When it happens

Trigger: new ReactFlightWebpackPlugin({isServer: true, ...}) — any attempt to make the plugin emit server artifacts.

Common situations: Assuming options must mirror each other for client and server webpack builds | Following architecture docs that describe a server compiler pass that has no implementation yet | Copy-pasting a config template with isServer gated on an env var

Related errors

• React Server Plugin: You must specify the isServer option as
• Could not find the module "${modulePath}" in the React Clien
• The module "${modulePath}" is marked as an async ESM module
• Use react-server-dom-webpack/client instead.
• Use react-server-dom-webpack/client instead.

AI-assisted analysis of facebook/react@eafeac097b (2026-08-21). Data as JSON: /api/errors/04bd842be251943b. Report an issue: GitHub.