WordPress at a glance
filter is not described

tiny_mce_before_init filter-hook . WP 2.5.0

Filters the TinyMCE config before init.


add_filter( 'tiny_mce_before_init', 'filter_function_name_8999', 10, 2 );
function filter_function_name_8999( $mceInit, $editor_id ){
	// filter...

	return $mceInit;
An array with TinyMCE config.
Unique editor identifier, e.g. 'content'.

Where the hook is called

wp-includes/class-wp-editor.php 706
$mceInit = apply_filters( 'tiny_mce_before_init', $mceInit, $editor_id );
wp-includes/script-loader.php 697
$tinymce_settings = apply_filters( 'tiny_mce_before_init', $tinymce_settings, 'classic-block' );

Where the hook is used (in WP core)

wp-includes/default-filters.php 232
add_filter( 'tiny_mce_before_init', '_mce_set_direction' );