Utility function for recursively resolving the absolute path of each file with in a directory and it's subdirectories

fs.util.ts

import fs from 'fs';
import path from 'path';

/**
 * resolveFilePaths returns the absolute paths of files contained with a
 * directory and it's sub directories.
 * @param dirPath the parent path
 * @returns The absolute paths of the files
 */
export async function resolveFilePaths(dirPath: string): Promise<string[]> {
  const parentDir = path.resolve(dirPath);
  const fileNames = await fs.promises.readdir(parentDir);
  const filePaths = fileNames.map((fname) => path.join(parentDir, fname));
  const stats = await Promise.all(filePaths.map((p) => fs.promises.stat(p)));

  const resolvedPaths: string[] = [];
  const subDirPromises: Promise<string[]>[] = [];

  for (let i = 0, len = filePaths.length; i < len; i++) {
    stats[i].isDirectory()
      ? subDirPromises.push(resolveFilePaths(filePaths[i]))
      : resolvedPaths.push(filePaths[i]);
  }

  const subDirFpaths = await Promise.all(subDirPromises);
  return resolvedPaths.concat(...subDirFpaths);
}