sort a stack with another stack

sortStack.js

'use strict';

function print(arr) {
	var res = '';
	for (var i = 0; i < arr.length; i++) {
		res += arr[i];
	};
	return res;
}

function sortStack(stack) {
	var resultStack = [];

	while(!!stack.length) {
		var tmp = stack.pop();
		while(!!resultStack.length && tmp > resultStack[resultStack.length-1]) {
			var resultStackPeek = resultStack.pop();
			stack.push(resultStackPeek);
		}
		resultStack.push(tmp);
		console.log('stack: %s    resultStack: %s', print(stack), print(resultStack));
	}

	return resultStack;
}