Sahi Browser Function Manager

BrowserFuncs.js

/**
 * This utility allows us to ignore using Sahi's <browser> </browser> tags for defining functions that should be run on the browser.
 * Instead we can simply call these utilities to pass functions back and forth between the two, which is super useful.
 */
var $Browser = (function ($Browser) {

	/**
	 * Adds a function to the window object on the browser side of things.
	 *
	 * @param $key - The name that should be assigned to the function on the browser.
	 * @param $func - The function that should be used.
	 */
	$Browser.addFunction = function ($key, $func) {
		if (!_condition(window.hasOwnProperty($key))) {
			_call(window[$key] = $func);
		} else {
			_fail("Function already exists on window object.");
		}
	};

	/**
	 * Calls a function on the window object and passes along any provided arguments after the key.
	 *
	 * @param $key {string} The name of the function you want to call.
	 * @param [$args] {...} Any arguments that need to be provided to the function you are calling.
	 *
	 * @returns {*} The result of the function you defined, (or nothing if a void function).
	 */
	$Browser.callFunction = function ($key, $args) {
		if (_condition(window.hasOwnProperty($key))) {
			var $args = [].splice.call(arguments, 1);
			return _fetch(window.callFunction($key, $args));
		} else {
			_fail("Requested function did not exist on the window object.");
		}
	};

	/**
	 * Redefines a function on the window object using the provided key. This is just to avoid developer stupidity.
	 *
	 * @param $key {string} The name of the function you want to redefine
	 * @param $func {Function} The function to be defined for the given key.
	 */
	$Browser.redefineFunction = function ($key, $func) {
		if (_condition(window.hasOwnProperty($key))) {
			_call(window[$key] = $func);
		} else {
			_fail("The function does not yet exist and therefore cannot be redefined.");
		}
	};

	/**
	 * Removes a function definition for a given key on the browser.
	 *
	 * @param $key {string} The name of the function to be removed.
	 */
	$Browser.removeFunction = function ($key) {
		if (_condition(window.hasOwnProperty($key))) {
			_call(window[$key] = undefined);
		} else {
			_fail("The function did not exist and so cannot be removed.");
		}
	};

	return $Browser;
})($Browser || {});

example.js

$Browser.addFunction("sibling", function (node) {
	return node.nextElementSibling;
});

var $results = $Browser.callFunction("sibling",_link({id:"_sahi_ignore_1"}));
_highlight($results);

supportingFuncs.js

/**
 * This function provides a work around to avoid using these browser tags elsewhere, instead we can call browser side functions
 * straight from a sahi script file and get the appropriate result on the proxy side.
 */

<browser>

function callFunction($name, $args){
	return window[$name].apply(window, $args);
}

</browser>