Walking a directory tree synchronously with Node.js 6+

walk.js

const fs = require('fs');

function walk(root) {
  const files = [];
  const dirs = [root];
  while (dirs.length) {
    const dir = dirs.shift();
    const dircontent = fs.readdirSync(dir).map(file => path.join(dir, file));
    const [newDirs, newFiles] = partition(dircontent, file => fs.statSync(file).isDirectory());
    files.push(...newFiles);
    dirs.push(...newDirs);
  }
  return files;
  
  // can be replaced by _.partition
  function partition(items, predicate) {
    return items.reduce((partitions, item) => {
      const partitionIndex = +!predicate(item);
      partitions[partitionIndex].push(item);
      return partitions;
    }, [[], []]);
  }
}