function FileCollection(type, layout, config) {
    _classCallCheck(this, FileCollection);

    this.type = type;
    this.layout = layout;
    this.config = config;
    this.files = [];
    this[type] = this.files;
  }
Represents a file collection.
@constructor
@param {string} type - The type of file collection (i.e. posts, pages).
@param {object} layout - The layouts of the file collection type.