Create a directory if it doesn't exist using Node.js

When working with files and directories in Node.js, you might want to create a directory, if it doesn't exist yet. The default behavior of the filesystem methods in Node.js is to throw an error if the directory already exists, so you need to roll up your own solution for this task.
Most commonly, you'll want to create a directory asynchronously, using fs.mkdir(). This method returns a Promise, that will reject if the directory already exists. In order to remedy that, we can use fs.access() to check if the directory exists, and then create it if it doesn't.
While the asynchronous approach is generally preferred, you might want to create a directory synchronously in some cases. You can use fs.existsSync() to check if the directory exists, and fs.mkdirSync() to create it.

import { access, mkdir } from 'fs/promises';

const createDirIfNotExists = dir =>
  access(dir)
    .then(() => undefined)
    .catch(() => mkdir(dir));

createDirIfNotExists('test');
// Asynchronously creates the directory 'test', if it doesn't exist

While the asynchronous approach is generally preferred, you might want to create a directory synchronously in some cases. You can use fs.existsSync() to check if the directory exists, and fs.mkdirSync() to create it.

From 30-seconds-of-code: create-directory-if-not-exists