range.js

function range(start, end, step) {
	if (arguments.length < 1)
		throw new TypeError('range expected at least 1 arguments, got 0');

	if (arguments.length < 2)
		end = start, start = 0;

	if (arguments.length < 3)
		step = 1;

	start |= 0, end |= 0, step |= 0;

	if (!step)
		throw new Error('range() step argument must not be zero');

	if (step < 0)
		for (var i = start; end < i; i += step)
			yield i;
	else
		for (var i = start; i < end; i += step)
			yield i;
}