code: function mkdir(dirPath, callback) {
    // Credits: https://github.com/substack/node-mkdirp
  
    // Recursively go through the parents.
    const recurse = () => {
      mkdir(path.dirname(dirPath), (error) => {
        if (error) {
          async.nextTick(callback, error);
          return;
        }
  
        // Try again.
        mkdir(dirPath, callback);
      });
    };
  
    // Plan B for when things seem to go wrong.
    const fallBack = () => {
      fs.stat(dirPath, (error, stat) => {
        if (error || !stat.isDirectory()) {
          async.nextTick(
            callback,
            new Error(`${dirPath}: Could not create the directory`)
          );
          return;
        }
  
        async.nextTick(callback, null);
      });
    };
  
    fs.mkdir(dirPath, (error) => {
      if (!error) {
        async.nextTick(callback, null);
        return;
      }
  
      switch (error.code) {
        case 'ENOENT':
          recurse();
          break;
        default:
          fallBack();
          break;
      }
    });
  }
docs: Create a directory and any missing parent directory.