async _registerEntryPoint()

in packages/metro/src/HmrServer.js [97:188]
79 lines of code
7 McCabe index (conditional complexity)

  async _registerEntryPoint(
    client: Client,
    requestUrl: string,
    sendFn: (data: string) => void,
  ): Promise<void> {
    requestUrl = this._config.server.rewriteRequestUrl(requestUrl);
    const clientUrl = nullthrows(url.parse(requestUrl, true));
    const options = parseOptionsFromUrl(
      requestUrl,
      new Set(this._config.resolver.platforms),
      BYTECODE_VERSION,
    );
    const {entryFile, transformOptions, graphOptions} =
      splitBundleOptions(options);

    /**
     * `entryFile` is relative to projectRoot, we need to use resolution function
     * to find the appropriate file with supported extensions.
     */
    const resolutionFn = await transformHelpers.getResolveDependencyFn(
      this._bundler.getBundler(),
      transformOptions.platform,
    );
    const resolvedEntryFilePath = resolutionFn(
      (this._config.server.unstable_serverRoot ?? this._config.projectRoot) +
        '/.',
      entryFile,
    );
    const graphId = getGraphId(resolvedEntryFilePath, transformOptions, {
      shallow: graphOptions.shallow,
      experimentalImportBundleSupport:
        this._config.transformer.experimentalImportBundleSupport,
    });
    const revPromise = this._bundler.getRevisionByGraphId(graphId);
    if (!revPromise) {
      send([sendFn], {
        type: 'error',
        body: formatBundlingError(new GraphNotFoundError(graphId)),
      });
      return;
    }

    const {graph, id} = await revPromise;
    client.revisionIds.push(id);

    let clientGroup = this._clientGroups.get(id);
    if (clientGroup != null) {
      clientGroup.clients.add(client);
    } else {
      // Prepare the clientUrl to be used as sourceUrl in HMR updates.
      clientUrl.protocol = 'http';
      const {
        dev,
        minify,
        runModule,
        bundleEntry: _bundleEntry,
        ...query
      } = clientUrl.query || {};
      clientUrl.query = {
        ...query,
        dev: dev || 'true',
        minify: minify || 'false',
        modulesOnly: 'true',
        runModule: runModule || 'false',
        shallow: 'true',
      };
      clientUrl.search = '';

      clientGroup = {
        clients: new Set([client]),
        clientUrl,
        revisionId: id,
        unlisten: (): void => unlisten(),
      };

      this._clientGroups.set(id, clientGroup);

      const unlisten = this._bundler.getDeltaBundler().listen(
        graph,
        debounceAsyncQueue(
          // $FlowFixMe[method-unbinding] added when improving typing for this parameters
          this._handleFileChange.bind(this, clientGroup, {
            isInitialUpdate: false,
          }),
          50,
        ),
      );
    }

    await this._handleFileChange(clientGroup, {isInitialUpdate: true});
    send([sendFn], {type: 'bundle-registered'});
  }