has_filter() WordPress Function
The has_filter() function is used to check if a given filter has been registered with WordPress. It can be used with either the name of the filter or the name of the hook.
has_filter( string $hook_name, callable|string|array|false $callback = false ) #
Checks if any filter has been registered for a 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)(Required)The name of the filter hook.
- $callback
(callable|string|array|false)(Optional) The callback to check for. This function 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/plugin.php
function has_filter( $hook_name, $callback = false ) {
global $wp_filter;
if ( ! isset( $wp_filter[ $hook_name ] ) ) {
return false;
}
return $wp_filter[ $hook_name ]->has_filter( $hook_name, $callback );
}
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Changelog
| Version | Description |
|---|---|
| 2.5.0 | Introduced. |