Custom dependency to set a field as required based on another field's value

set_required.ext.php

<?php

/* This example sets the Status Description field to required
if the Status field is set to 'Dead' within Leads module.

File: ./custom/Extension/modules/Leads/Ext/Dependencies/set_required.ext.php */

$dependencies['Leads']['req_status_desc_dep'] = array(
	'hooks' => array("edit"),
	'trigger' => 'true', 
	'triggerFields' => array('status'),
	'onload' => true,
	'actions' => array(
		array(
			'name' => 'SetRequired',
			'params' => array(
				'target' => 'status_description',
				'label' => 'LBL_STATUS_DESCRIPTION',
				'value' => 'equal($status, "Dead")' 
			)
		),
	),
	//Actions fire if the trigger is false. Optional.
	'notActions' => array(),
);