text: const config = require('config');
  
  const ModelPath = '../../models/';
  const Upload = require(ModelPath + 'Upload.js');
  
  const exists = async id =>
      await Upload.countDocuments({id: id}) === 1;
  
  const generate = async () => {
      const charset = config.get('Upload.charset');
      const len = config.get('Upload.idLength');
  
      const id = [...Array(len)]
          .map(() => charset.charAt(Math.floor(Math.random() * charset.length)))
          .join('');
  
      return await exists(id)
          ? generate()
          : id;
  };
  
  exports.generate = generate;
  exports.exists = exists;