Simple Node.js script which simplify nested directory tree

smartflatten.js

'use strict';
const fs = require('fs');
const path = require('path');

let directories = process.argv.slice(2).map(resolveDir);

while(directories.length) {
  const subDir = [];
  for(const dir of directories) {
    if(!ensureFolder(dir)) continue;
    console.log('Scanning %s...', dir);
    const files = fs.readdirSync(dir);
    if(!files.length) {
      console.log('Empty folder detected, trying to delete it...');
      try {
        fs.rmdirSync(dir);
      } catch(e) {
        console.error(e.message || e);
      }
      continue;
    }
    const dirs = files.map(resolveDir, dir).filter(ensureFolder);
    if(dirs.length === 1 && files.length === 1) {
      console.log('Found 1 subfolder inside, trying to flatten it.');
      try {
        const tempDir = path.resolve(dir, '__temp_' + Date.now()); // Prevent same name
        fs.renameSync(dirs[0], tempDir);
        fs.readdirSync(tempDir).forEach(moveFile, {
          from: tempDir,
          to: dir
        });
        fs.rmdirSync(tempDir);
        subDir.push(dir); // Rescan it later
      } catch(e) {
        console.error(e.message || e);
      }
      continue;
    }
    if(dirs.length) {
      console.log('Found %d subfolder(s) inside, which will be scanned later.', dirs.length);
      Array.prototype.push.apply(subDir, dirs);
    }
  }
  directories = subDir;
}

function resolveDir(cd) {
  return cd && path.resolve(this || process.cwd, cd);
}

function ensureFolder(cd) {
  return cd && fs.existsSync(cd) && fs.statSync(cd).isDirectory();
}

function moveFile(filePath) {
  return fs.renameSync(path.resolve(this.from, filePath), path.resolve(this.to, filePath));
}