react/packages/react-server-dom-turbopack/src/__tests__/ReactFlightTurbopackDOMEdge-test.js

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @emails react-core
 */

'use strict';

// Polyfills for test environment
global.ReadableStream =
  require('web-streams-polyfill/ponyfill/es6').ReadableStream;
global.WritableStream =
  require('web-streams-polyfill/ponyfill/es6').WritableStream;
global.TextEncoder = require('util').TextEncoder;
global.TextDecoder = require('util').TextDecoder;

let clientExports;
let turbopackMap;
let turbopackModules;
let React;
let ReactServer;
let ReactDOMServer;
let ReactServerDOMServer;
let ReactServerDOMClient;
let use;
let serverAct;

describe('ReactFlightTurbopackDOMEdge', () => {
  beforeEach(() => {
    jest.resetModules();

    serverAct = require('internal-test-utils').serverAct;

    // Simulate the condition resolution
    jest.mock('react', () => require('react/react.react-server'));
    jest.mock('react-server-dom-turbopack/server', () =>
      require('react-server-dom-turbopack/server.edge'),
    );

    const TurbopackMock = require('./utils/TurbopackMock');
    clientExports = TurbopackMock.clientExports;
    turbopackMap = TurbopackMock.turbopackMap;
    turbopackModules = TurbopackMock.turbopackModules;

    ReactServer = require('react');
    ReactServerDOMServer = require('react-server-dom-turbopack/server.edge');

    jest.resetModules();
    __unmockReact();

    React = require('react');
    ReactDOMServer = require('react-dom/server.edge');
    ReactServerDOMClient = require('react-server-dom-turbopack/client.edge');
    use = React.use;
  });

  async function readResult(stream) {
    const reader = stream.getReader();
    let result = '';
    while (true) {
      const {done, value} = await reader.read();
      if (done) {
        return result;
      }
      result += Buffer.from(value).toString('utf8');
    }
  }

  function normalizeCodeLocInfo(str) {
    return (
      str &&
      str.replace(/^ +(?:at|in) ([\S]+)[^\n]*/gm, function (m, name) {
        return '    in ' + name + (/\d/.test(m) ? ' (at **)' : '');
      })
    );
  }

  function createDelayedStream(
    stream: ReadableStream<Uint8Array>,
  ): ReadableStream<Uint8Array> {
    return new ReadableStream({
      async start(controller) {
        const reader = stream.getReader();
        while (true) {
          const {done, value} = await reader.read();
          if (done) {
            controller.close();
          } else {
            // Artificially delay between enqueuing chunks.
            await new Promise(resolve => setTimeout(resolve));
            controller.enqueue(value);
          }
        }
      },
    });
  }

  it('should allow an alternative module mapping to be used for SSR', async () => {
    function ClientComponent() {
      return <span>Client Component</span>;
    }
    // The Client build may not have the same IDs as the Server bundles for the same
    // component.
    const ClientComponentOnTheClient = clientExports(ClientComponent);
    const ClientComponentOnTheServer = clientExports(ClientComponent);

    // In the SSR bundle this module won't exist. We simulate this by deleting it.
    const clientId = turbopackMap[ClientComponentOnTheClient.$$id].id;
    delete turbopackModules[clientId];

    // Instead, we have to provide a translation from the client meta data to the SSR
    // meta data.
    const ssrMetadata = turbopackMap[ClientComponentOnTheServer.$$id];
    const translationMap = {
      [clientId]: {
        '*': ssrMetadata,
      },
    };

    function App() {
      return <ClientComponentOnTheClient />;
    }

    const stream = await serverAct(() =>
      ReactServerDOMServer.renderToReadableStream(<App />, turbopackMap),
    );
    const response = ReactServerDOMClient.createFromReadableStream(stream, {
      serverConsumerManifest: {
        moduleMap: translationMap,
        moduleLoading: null,
      },
    });

    function ClientRoot() {
      return use(response);
    }

    const ssrStream = await serverAct(() =>
      ReactDOMServer.renderToReadableStream(<ClientRoot />),
    );
    const result = await readResult(ssrStream);
    expect(result).toEqual('<span>Client Component</span>');
  });

  // @gate __DEV__
  it('can transport debug info through a separate debug channel', async () => {
    function Thrower() {
      throw new Error('ssr-throw');
    }

    const ClientComponentOnTheClient = clientExports(
      Thrower,
      123,
      'path/to/chunk.js',
    );

    const ClientComponentOnTheServer = clientExports(Thrower);

    function App() {
      return ReactServer.createElement(
        ReactServer.Suspense,
        null,
        ReactServer.createElement(ClientComponentOnTheClient, null),
      );
    }

    let debugReadableStreamController;

    const debugReadableStream = new ReadableStream({
      start(controller) {
        debugReadableStreamController = controller;
      },
    });

    const rscStream = await serverAct(() =>
      ReactServerDOMServer.renderToReadableStream(
        ReactServer.createElement(App, null),
        turbopackMap,
        {
          debugChannel: {
            writable: new WritableStream({
              write(chunk) {
                debugReadableStreamController.enqueue(chunk);
              },
              close() {
                debugReadableStreamController.close();
              },
            }),
          },
        },
      ),
    );

    function ClientRoot({response}) {
      return use(response);
    }

    const serverConsumerManifest = {
      moduleMap: {
        [turbopackMap[ClientComponentOnTheClient.$$id].id]: {
          '*': turbopackMap[ClientComponentOnTheServer.$$id],
        },
      },
      moduleLoading: null,
    };

    const response = ReactServerDOMClient.createFromReadableStream(
      // Create a delayed stream to simulate that the RSC stream might be
      // transported slower than the debug channel, which must not lead to a
      // `Connection closed` error in the Flight client.
      createDelayedStream(rscStream),
      {
        serverConsumerManifest,
        debugChannel: {readable: debugReadableStream},
      },
    );

    let ownerStack;

    const ssrStream = await serverAct(() =>
      ReactDOMServer.renderToReadableStream(
        <ClientRoot response={response} />,
        {
          onError(err, errorInfo) {
            ownerStack = React.captureOwnerStack
              ? React.captureOwnerStack()
              : null;
          },
        },
      ),
    );

    const result = await readResult(ssrStream);

    expect(normalizeCodeLocInfo(ownerStack)).toBe('\n    in App (at **)');

    expect(result).toContain(
      'Switched to client rendering because the server rendering errored:\n\nssr-throw',
    );
  });
});