jQuery implementation of ECMAScript 5’s reduce() method (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce).

jquery.reduce.js

$.fn.reduce = function(fnReduce, initialValue) {
	var values = this,
		previousValue = initialValue;

	values.each(function(index, currentValue) {
		previousValue = fnReduce.call(currentValue, previousValue, currentValue, index, values);
	});

	return previousValue;
};

You shouldn't attach it to $.fn as it doesn't operate on the DOM. Besides, there's no need for fnReduce.apply, for your use case call works better.

Thanks for your feedback! It reduces the current matched set, which is why it’s attached to $.fn. The change to call is definitely worth the effort though, thanks for pointing this out.