async _getChangedDependencies()

in packages/metro/src/DeltaBundler/DeltaCalculator.js [196:257]

• 49 lines of code
• 5 McCabe index (conditional complexity)

  async _getChangedDependencies(
    modifiedFiles: Set<string>,
    deletedFiles: Set<string>,
  ): Promise<DeltaResult<T>> {
    if (!this._graph.dependencies.size) {
      const {added} = await initialTraverseDependencies(
        this._graph,
        this._options,
      );

      return {
        added,
        modified: new Map(),
        deleted: new Set(),
        reset: true,
      };
    }

    // If a file has been deleted, we want to invalidate any other file that
    // depends on it, so we can process it and correctly return an error.
    deletedFiles.forEach((filePath: string) => {
      const module = this._graph.dependencies.get(filePath);

      if (module) {
        module.inverseDependencies.forEach((path: string) => {
          // Only mark the inverse dependency as modified if it's not already
          // marked as deleted (in that case we can just ignore it).
          if (!deletedFiles.has(path)) {
            modifiedFiles.add(path);
          }
        });
      }
    });

    // We only want to process files that are in the bundle.
    const modifiedDependencies = Array.from(modifiedFiles).filter(
      (filePath: string) => this._graph.dependencies.has(filePath),
    );

    // No changes happened. Return empty delta.
    if (modifiedDependencies.length === 0) {
      return {
        added: new Map(),
        modified: new Map(),
        deleted: new Set(),
        reset: false,
      };
    }

    const {added, modified, deleted} = await traverseDependencies(
      modifiedDependencies,
      this._graph,
      this._options,
    );

    return {
      added,
      modified,
      deleted,
      reset: false,
    };
  }