code: function contains(file, pattern, options) {
    options = _.sanitize(options, {encoding: 'utf-8'});
    if (!exists(file)) return false;
    const text = read(file, options);
    if (_.isRegExp(pattern)) {
      return !!text.match(pattern);
    } else {
      return (text.search(_escapeRegExp(pattern)) !== -1);
    }
  }
docs: Check if file contents contains a given pattern
  @function $file~contains
  @param {string} file - File path to check its contents
  @param {string|RegExp} pattern - Glob like pattern or regexp to match
  @param {Object} [options]
  @param {string} [options.encoding=utf-8] - Encoding used to read the file
  @returns {boolean} - Whether the contents of the file match or not the pattern
  @example
  // Check if service has started successfully
  $file.contains('logs/service.log', /.*service.*started\s*successfully/);
  // => true