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_namestringoptional- The name of the filter hook. Default empty.
$callbackcallable|string|array|falseoptional- The callback to check for.
This method can be called unconditionally to speculatively check a callback that may or may not exist.Default:
false $priorityint|falseoptional- The specific priority at which to check for the callback.
Default:
false
Source
public function has_filter( $hook_name = '', $callback = false, $priority = false ) {
if ( false === $callback ) {
return $this->has_filters();
}
$function_key = _wp_filter_build_unique_id( $hook_name, $callback, false );
if ( ! $function_key ) {
return false;
}
if ( is_int( $priority ) ) {
return isset( $this->callbacks[ $priority ][ $function_key ] );
}
foreach ( $this->callbacks as $callback_priority => $callbacks ) {
if ( isset( $callbacks[ $function_key ] ) ) {
return $callback_priority;
}
}
return false;
}
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