search(attribute, search) {
    this[this.type] = this.files.filter((file) => {
      var attr = file[attribute].toLowerCase().trim();
      return attr.indexOf(search.toLowerCase().trim()) >= 0;
    });
  }
Search file collection by attribute.
@method
@param {string} attribute - Attribue in file to search.
@param {string} search - Search query.
@returns {object} File object