Get User’s Capabilities in WordPress

The function below can be used to get all of a user’s capabilities:

/**
 * Get user's capabilities.
 *
 * @param  int|WP_User $user The user ID or object. Default is the current user.
 *
 * @return array             The user's capabilities or empty array if none or user doesn't exist.
 */
function km_get_user_capabilities( $user = null ) {
	$user = $user ? new WP_User( $user ) : wp_get_current_user();

	return array_keys( $user->allcaps );
}

If you pass a user ID to it, you will get that user’s capabilities. If you don’t pass anything to it, you’ll get the current user’s capabilities instead.

It will return an array of capabilities like the one pictured below, or an empty array if the user has no capabilities or doesn’t exist.