protected function get_json_id( $key, $extra = '' ) {
		return $this->get_slug() . '_' . papi_slugify( $key ) . ( empty( $extra ) ? '' : '_' . $extra );
	}
protected function get_json_id( $key, $extra = '' ) {
		return $this->get_slug() . '_' . papi_slugify( $key ) . ( empty( $extra ) ? '' : '_' . $extra );
	}
protected function get_json_id ( $ key , $ extra = '' ) { return $ this -> get_slug ( ) . '_' . papi_slugify ( $ key ) . ( empty ( $ extra ) ? '' : '_' . $ extra ) ; }
Generate layout slug.

@param  string $key
@param  string $extra

@return string
Generate layout slug .