React DOM fizz server edge

一、作用

二、渲染为可读流

备注

• startFlowing() 由 ReactFizzServer#startFlowing 实现
• stopFlowing() 由 ReactFizzServer#stopFlowing 实现
• abort() 由 ReactFizzServer#abort 实现
• createResumableState() 由 ReactFizzConfigDOM#createResumableState 实现
• createRequest() 由 ReactFizzServer#createRequest 实现
• createRenderState() 由 ReactFizzConfigDOM#createRenderState 实现
• createRootFormatContext() 由 ReactFizzConfigDOM#createRootFormatContext 实现
• startWork() 由 ReactFizzServer#startWork 实现

function renderToReadableStream(
  children: ReactNodeList,
  options?: Options,
): Promise<ReactDOMServerReadableStream> {
  return new Promise((resolve, reject) => {
    let onFatalError;
    let onAllReady;
    const allReady = new Promise<void>((res, rej) => {
      onAllReady = res;
      onFatalError = rej;
    });

    function onShellReady() {
      const stream: ReactDOMServerReadableStream = new ReadableStream(
        {
          type: 'bytes',
          pull: (controller): ?Promise<void> => {
            startFlowing(request, controller);
          },
          cancel: (reason): ?Promise<void> => {
            stopFlowing(request);
            abort(request, reason);
          },
        },
        { highWaterMark: 0 },
      ) as any;
      // TODO: Move to sub-classing ReadableStream.
      // 待办事项：迁移到 ReadableStream 的子类化。
      stream.allReady = allReady;
      resolve(stream);
    }
    function onShellError(error: mixed) {
      // If the shell errors the caller of `renderToReadableStream` won't have access to `allReady`.
      // 如果 shell 出错，`renderToReadableStream` 的调用者将无法访问 `allReady`。
      // However, `allReady` will be rejected by `onFatalError` as well.
      // 然而，`allReady` 也会被 `onFatalError` 拒绝。
      // So we need to catch the duplicate, uncatchable fatal error in `allReady` to prevent a `UnhandledPromiseRejection`.
      // 因此我们需要在 `allReady` 中捕获重复的、无法捕获的致命错误，以防止 `UnhandledPromiseRejection`。
      allReady.catch(() => {});
      reject(error);
    }

    const onHeaders = options ? options.onHeaders : undefined;
    let onHeadersImpl;
    if (onHeaders) {
      onHeadersImpl = (headersDescriptor: HeadersDescriptor) => {
        onHeaders(new Headers(headersDescriptor));
      };
    }

    const resumableState = createResumableState(
      options ? options.identifierPrefix : undefined,
      options ? options.unstable_externalRuntimeSrc : undefined,
      options ? options.bootstrapScriptContent : undefined,
      options ? options.bootstrapScripts : undefined,
      options ? options.bootstrapModules : undefined,
    );
    const request = createRequest(
      children,
      resumableState,
      createRenderState(
        resumableState,
        options ? options.nonce : undefined,
        options ? options.unstable_externalRuntimeSrc : undefined,
        options ? options.importMap : undefined,
        onHeadersImpl,
        options ? options.maxHeadersLength : undefined,
      ),
      createRootFormatContext(options ? options.namespaceURI : undefined),
      options ? options.progressiveChunkSize : undefined,
      options ? options.onError : undefined,
      onAllReady,
      onShellReady,
      onShellError,
      onFatalError,
      options ? options.formState : undefined,
    );
    if (options && options.signal) {
      const signal = options.signal;
      if (signal.aborted) {
        abort(request, (signal as any).reason);
      } else {
        const listener = () => {
          abort(request, (signal as any).reason);
          signal.removeEventListener('abort', listener);
        };
        signal.addEventListener('abort', listener);
      }
    }
    startWork(request);
  });
}

三、恢复

备注

• startFlowing() 由 ReactFizzServer#startFlowing 实现
• stopFlowing() 由 ReactFizzServer#stopFlowing 实现
• abort() 由 ReactFizzServer#abort 实现
• resumeRequest() 由 ReactFizzServer#resumeRequest 实现
• resumeRenderState() 由 ReactFizzConfigDOM#resumeRenderState 实现
• startWork() 由 ReactFizzServer#startWork 实现

function resume(
  children: ReactNodeList,
  postponedState: PostponedState,
  options?: ResumeOptions,
): Promise<ReactDOMServerReadableStream> {
  return new Promise((resolve, reject) => {
    let onFatalError;
    let onAllReady;
    const allReady = new Promise<void>((res, rej) => {
      onAllReady = res;
      onFatalError = rej;
    });

    function onShellReady() {
      const stream: ReactDOMServerReadableStream = new ReadableStream(
        {
          type: 'bytes',
          pull: (controller): ?Promise<void> => {
            startFlowing(request, controller);
          },
          cancel: (reason): ?Promise<void> => {
            stopFlowing(request);
            abort(request, reason);
          },
        },
        { highWaterMark: 0 },
      ) as any;
      // TODO: Move to sub-classing ReadableStream.
      // 待办事项：迁移到 ReadableStream 的子类化。
      stream.allReady = allReady;
      resolve(stream);
    }
    function onShellError(error: mixed) {
      // If the shell errors the caller of `renderToReadableStream` won't have access to `allReady`.
      // 如果 shell 出错，`renderToReadableStream` 的调用者将无法访问 `allReady`。
      // However, `allReady` will be rejected by `onFatalError` as well.
      // 然而，`allReady` 也会被 `onFatalError` 拒绝。
      // So we need to catch the duplicate, uncatchable fatal error in `allReady` to prevent a `UnhandledPromiseRejection`.
      // 因此我们需要在 `allReady` 中捕获重复的、无法捕获的致命错误，以防止 `UnhandledPromiseRejection`。
      allReady.catch(() => {});
      reject(error);
    }
    const request = resumeRequest(
      children,
      postponedState,
      resumeRenderState(
        postponedState.resumableState,
        options ? options.nonce : undefined,
      ),
      options ? options.onError : undefined,
      onAllReady,
      onShellReady,
      onShellError,
      onFatalError,
    );
    if (options && options.signal) {
      const signal = options.signal;
      if (signal.aborted) {
        abort(request, (signal as any).reason);
      } else {
        const listener = () => {
          abort(request, (signal as any).reason);
          signal.removeEventListener('abort', listener);
        };
        signal.addEventListener('abort', listener);
      }
    }
    startWork(request);
  });
}

四、工具

1. 确保正确的同构 React 版本

在逻辑顶部检验 React 版本是否正确的全局副作用。

ensureCorrectIsomorphicReactVersion();

五、类型

1. 一次性选项

// 一次性选项
type NonceOption =
  | string
  | {
      script?: string;
      style?: string;
    };

// 选项
type Options = {
  identifierPrefix?: string;
  namespaceURI?: string;
  nonce?: NonceOption;
  bootstrapScriptContent?: string;
  bootstrapScripts?: Array<string | BootstrapScriptDescriptor>;
  bootstrapModules?: Array<string | BootstrapScriptDescriptor>;
  progressiveChunkSize?: number;
  signal?: AbortSignal;
  onError?: (error: mixed, errorInfo: ErrorInfo) => ?string;
  unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor;
  importMap?: ImportMap;
  formState?: ReactFormState<any, any> | null;
  onHeaders?: (headers: Headers) => void;
  maxHeadersLength?: number;
};

// 恢复选项
type ResumeOptions = {
  nonce?: NonceOption;
  signal?: AbortSignal;
  onError?: (error: mixed) => ?string;
  unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor;
};

// TODO: Move to sub-classing ReadableStream.
// 待办事项：迁移到 ReadableStream 的子类化。
// ReactDOM服务器可读流
type ReactDOMServerReadableStream = ReadableStream & {
  allReady: Promise<void>;
};

六、转导

• 从 ReactVersion 转导了 ReactVersion as version