Adding carbon cli the ability to process files from a directory

gistfile1.js

const util = require('util');
const exec = util.promisify(require('child_process').exec);
const fs = require( 'fs' );
const path = require( 'path' );
const codeSampleDir = './code-samples';

//Async forEach loop
async function asyncForEach(array, callback) {
  let arrayLength = array.length;
  for (let index = 0; index < arrayLength; index++) {
    await callback(array[index], index, array)
  }
}

// isDirectory helper function
function isDirectory (pathname) {
  return fs.statSync(pathname).isDirectory();
}

function buildImages (dir) {

    if (!isDirectory(dir)) {
      console.error(`The entry dir MUST be a directory. You've provided a file instead.`);
      process.exit(1);
    }

    try {
      // Reading source directory looking for images to convert
      fs.readdir( dir, function( err, files ) {

        // If an error happens exit the process.
        if (err) {
          console.error("Could not list the directory.\r\n", err);
          process.exit(1);
        }

        carbonStart(files, dir);

      });
    } catch (err) {
      console.error("The directory can't be read. Try later.");
    }

}

buildImages(codeSampleDir);

// Get Carbon image method
async function getCarbonImage(fileName, dir) {
  let file = path.join(dir, fileName);
  const { stdout, stderr } = await exec(`carbon-now ${file} -l 'images'`);
  console.log('stdout:', stdout);
  console.log('stderr:', stderr);
}

//carbon routine
const carbonStart = async(files, dir) => {
  await asyncForEach(files, async function(file) {
    await getCarbonImage(file, dir);
  });
}