code: function checkOutput(input, output) {
    let reg = new RegExp('\\$1');
    if (reg.test(output)) {
      if (Array.isArray(input)) {
        const outputMin = input.map(file => {
          return utils.setFileNameMin(file, output);
        });
        return { output: outputMin };
      } else {
        return { output: utils.setFileNameMin(input, output) };
      }
    }
  }
docs: Check the output path, searching for $1
  if exist, returns the path remplacing $1 by file name
  
  @param {String|Array} input - Path file
  @param {String} output - Path to the output file
  @return {Object}