WP_Scripts::get_eligible_loading_strategy( string $handle ): string

1049	private function get_eligible_loading_strategy( $handle ) {1050		$intended_strategy = (string) $this->get_data( $handle, 'strategy' );1051 1052		// Bail early if there is no intended strategy.1053		if ( ! $intended_strategy ) {1054			return '';1055		}1056 1057		/*1058		 * If the intended strategy is 'defer', limit the initial list of eligible1059		 * strategies, since 'async' can fallback to 'defer', but not vice-versa.1060		 */1061		$initial_strategy = ( 'defer' === $intended_strategy ) ? array( 'defer' ) : null;1062 1063		$eligible_strategies = $this->filter_eligible_strategies( $handle, $initial_strategy );1064 1065		// Return early once we know the eligible strategy is blocking.1066		if ( empty( $eligible_strategies ) ) {1067			return '';1068		}1069 1070		return in_array( 'async', $eligible_strategies, true ) ? 'async' : 'defer';1071	}