Valid Hook Name

Use lowercase letters in action and filter names. Separate words using underscores.

Valid: lowercase hook name.

do_action( <em>'prefix_hook_name'</em>, $var );

Invalid: mixed case hook name.

do_action( <em>'Prefix_Hook_NAME'</em>, $var );

Valid: words separated by underscores.

apply_filters( <em>'prefix_hook_name'</em>, $var );

Invalid: using non-underscore characters to separate words.

apply_filters( <em>'prefix\hook-name'</em>, $var );