wp_get_speculation_rules_configuration(): array<string,

26function wp_get_speculation_rules_configuration(): ?array {27	// By default, speculative loading is only enabled for sites with pretty permalinks when no user is logged in.28	if ( ! is_user_logged_in() && get_option( 'permalink_structure' ) ) {29		$config = array(30			'mode'      => 'auto',31			'eagerness' => 'auto',32		);33	} else {34		$config = null;35	}36 37	/**38	 * Filters the way that speculation rules are configured.39	 *40	 * The Speculation Rules API is a web API that allows to automatically prefetch or prerender certain URLs on the41	 * page, which can lead to near-instant page load times. This is also referred to as speculative loading.42	 *43	 * There are two aspects to the configuration:44	 * * The "mode" (whether to "prefetch" or "prerender" URLs).45	 * * The "eagerness" (whether to speculatively load URLs in an "eager", "moderate", or "conservative" way).46	 *47	 * By default, the speculation rules configuration is decided by WordPress Core ("auto"). This filter can be used48	 * to force a certain configuration, which could for instance load URLs more or less eagerly.49	 *50	 * For logged-in users or for sites that are not configured to use pretty permalinks, the default value is `null`,51	 * indicating that speculative loading is entirely disabled.52	 *53	 * @since 6.8.054	 * @see https://developer.chrome.com/docs/web-platform/prerender-pages55	 *56	 * @param array<string, string>|null $config Associative array with 'mode' and 'eagerness' keys, or `null`. The57	 *                                           default value for both of the keys is 'auto'. Other possible values58	 *                                           for 'mode' are 'prefetch' and 'prerender'. Other possible values for59	 *                                           'eagerness' are 'eager', 'moderate', and 'conservative'. The value60	 *                                           `null` is used to disable speculative loading entirely.61	 */62	$config = apply_filters( 'wp_speculation_rules_configuration', $config );63 64	// Allow the value `null` to indicate that speculative loading is disabled.65	if ( null === $config ) {66		return null;67	}68 69	// Sanitize the configuration and replace 'auto' with current defaults.70	$defaults          = wp_get_speculation_rules_default_configuration();71	$default_mode      = $defaults['mode'];72	$default_eagerness = $defaults['eagerness'];73 74	if ( ! is_array( $config ) ) {75		return array(76			'mode'      => $default_mode,77			'eagerness' => $default_eagerness,78		);79	}80	if (81		! isset( $config['mode'] ) ||82		'auto' === $config['mode'] ||83		! WP_Speculation_Rules::is_valid_mode( $config['mode'] )84	) {85		$config['mode'] = $default_mode;86	}87	if (88		! isset( $config['eagerness'] ) ||89		'auto' === $config['eagerness'] ||90		! WP_Speculation_Rules::is_valid_eagerness( $config['eagerness'] ) ||91		// 'immediate' is a valid eagerness, but for safety WordPress does not allow it for document-level rules.92		'immediate' === $config['eagerness']93	) {94		$config['eagerness'] = $default_eagerness;95	}96 97	return array(98		'mode'      => $config['mode'],99		'eagerness' => $config['eagerness'],100	);101}
When	Instructions	Calls it makes
`is_user_logged_in() && $config === null`	12	`is_user_logged_in(), apply_filters()`
`!is_user_logged_in() && $config === null`	16–17	`is_user_logged_in(), get_option(), apply_filters()`
`is_user_logged_in() && $config !== null`	21–37	`is_user_logged_in(), apply_filters(), wp_get_speculation_rules_default_configuration()`
`!is_user_logged_in() && $config !== null`	25–42	`is_user_logged_in(), get_option(), apply_filters(), wp_get_speculation_rules_default_configuration()`
`is_user_logged_in() && $config !== null && is_array($config) && isset($config)`	38–46	`is_user_logged_in(), apply_filters(), wp_get_speculation_rules_default_configuration(), ::WP_Speculation_Rules()`
`!is_user_logged_in() && $config !== null && is_array($config) && isset($config)`	42–51	`is_user_logged_in(), get_option(), apply_filters(), wp_get_speculation_rules_default_configuration(), ::WP_Speculation_Rules()`
`is_user_logged_in() && $config !== null && is_array($config) && isset($config)`	47–52	`is_user_logged_in(), apply_filters(), wp_get_speculation_rules_default_configuration(), ::WP_Speculation_Rules(), ::WP_Speculation_Rules()`
`!is_user_logged_in() && $config !== null && is_array($config) && isset($config)`	51–57	`is_user_logged_in(), get_option(), apply_filters(), wp_get_speculation_rules_default_configuration(), ::WP_Speculation_Rules(), ::WP_Speculation_Rules()`