WP_Hook::has_filter() WordPress Method
The WP_Hook::has_filter() method is used to check if a certain filter has been registered with a WordPress hook. This can be useful for checking if a plugin or theme has registered a certain filter, and then taking action accordingly.
WP_Hook::has_filter( string $hook_name = '', callable|string|array|false $callback = false ) #
Checks if a specific callback has been registered for this hook.
Description
When using the $callback argument, this function may return a non-boolean value that evaluates to false (e.g. 0), so use the === operator for testing the return value.
Parameters
- $hook_name
(string)(Optional) The name of the filter hook.
Default value: ''
- $callback
(callable|string|array|false)(Optional) The callback to check for. This method can be called unconditionally to speculatively check a callback that may or may not exist.
Default value: false
Return
(bool|int) If $callback is omitted, returns boolean for whether the hook has anything registered. When checking a specific function, the priority of that hook is returned, or false if the function is not attached.
Source
File: wp-includes/class-wp-hook.php
public function has_filter( $hook_name = '', $callback = false ) {
if ( false === $callback ) {
return $this->has_filters();
}
$function_key = _wp_filter_build_unique_id( $hook_name, $callback, false );
if ( ! $function_key ) {
return false;
}
foreach ( $this->callbacks as $priority => $callbacks ) {
if ( isset( $callbacks[ $function_key ] ) ) {
return $priority;
}
}
return false;
}
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Changelog
| Version | Description |
|---|---|
| 4.7.0 | Introduced. |