Method attached

src/core/core.controller.js:1022–1030

()

    let detached; // eslint-disable-line prefer-const
    const attached = () => {
      _remove('attach', attached);

      this.attached = true;
      this.resize();

      _add('resize', listener);
      _add('detach', detached);
    };

    detached = () => {
      this.attached = false;