add language constants to Joomla component javascript - joomla

Question

My component includes a java script file:
$doc->addScript("/components/com_cam/js/cam.js");
I have several client side messages that I'd like to add with language constants, i.e.
<?php echo JText::_('COM_CAM_SEND_LABEL'); ?>
Easy enough in your front end php code like default.php but what about messages inside cam.js?
Such as my jquery validation:
messages: {
cam: {
required: "Enter a label",
minlength: jQuery.format("At least {0} characters required!"),
maxlength: jQuery.format("Maximum {0} characters allowed!")
}
}
What is the best practice for this?

Answer 1

In Joomla! 2.5 (since 1.6 I believe) there is JText::script() which adds support for adding language keys to a global array() so that your Javascript can access them.
First up, in your PHP you can call JText::script('COM_MYCOMPONENT_MSG1'); for each string you need translated in your Javascript.
The you can use the built-in Joomla.JText._('COM_MYCOMPONENT_MSG1') in your Javascript to retrieve it.
When you get to the point where there a lots of strings to be converted you may find it easier to just parse the javascript file at run time (in-efficient yada yada but for back-end admin screens not such a big deal).
/**
* Parses a javascript file looking for JText keys and then loads them ready for use.
*
* #param string $jsFile Path to the javascript file.
*
* #return bool
*/
public static function loadJSLanguageKeys($jsFile)
{
if (isset($jsFile))
{
$jsFile = JPATH_SITE . $jsFile;
}
else
{
return false;
}
if ($jsContents = file_get_contents($jsFile))
{
$languageKeys = array();
preg_match_all('/Joomla\.JText\._\(\'(.*?)\'\)\)?/', $jsContents, $languageKeys);
$languageKeys = $languageKeys[1];
foreach ($languageKeys as $lkey)
{
JText::script($lkey);
}
}
}

Answer 2

Make a helper function to build validation messages and add it to the head.
Something like bellow, just edit it to suit your needs
$messages = '(function ($) {
$.extend($.validator.messages, {
cam: {
required: "' . JText::_('COM_CAM_VALIDATION_REQUIRED') . '",
minlength: jQuery.format("' . JText::_('COM_CAM_VALIDATION_MINIMUM') . '"),
maxlength: jQuery.format("' . JText::_('COM_CAM_VALIDATION_MAXIMUM') . '")
}
});
}(jQuery));';
$doc = JFactory::getDocument();
$doc->addScriptDeclaration($messages);