Class InMemoryFileSystem

packages/worker-bundler/src/file-system.ts:42–75

 * and build pipelines where persistence is not required.
 */
export class InMemoryFileSystem implements FileSystem {
  private files: Map<string, string> = new Map();

  /**
   * @param files Optional initial file contents. Accepts either a plain object
   * (keys are paths, values are file contents) or a `Map`. Defaults to an
   * empty filesystem.
   */
  constructor(files: Record<string, string> | Map<string, string> = new Map()) {
    this.files = files instanceof Map ? files : new Map(Object.entries(files));
  }

  read(path: string): string | null {
    return this.files.get(path) ?? null;
  }

  write(path: string, content: string): void {
    this.files.set(path, content);
  }

  delete(path: string): void {
    this.files.delete(path);
  }

  list(prefix?: string): string[] {
    return Array.from(this.files.keys()).filter(
      (path) => prefix === undefined || path.startsWith(prefix)
    );
  }

  flush(): Promise<void> {
    return Promise.resolve();
  }
}

/**
 * A generic write-overlay on top of any `FileSystem`. Not re-exported from the