https://repl.it/CTU3/128 created by sethopia

Up and Down (1.3).js

/*
	UP & DOWN
	
	Create a function countUpThenDown() that takes a number n and logs all the numbers 0 to n and back to 0.
	
	eg)
		countUpThenDown(2) ==> 0 1 2 1 0
		countUpThenDown(11) ==> 0 1 2 3 4 5 6 7 8 9 10 11 10 9 8 7 6 5 4 3 2 1 0
*/

var countUpThenDown = function(n) {
	// loop from 0 to n and push to an array
	var arr = [];
	for (var i = 0; i <= n; i++) {
		arr.push(i);
	}
	// loop down from n-1 and log along the way back to 0
	for (i = n-1; i >= 0; i--) {
		arr.push(i);
	}
	// log arr
		console.log(arr.join(" "));
}

countUpThenDown(2);
countUpThenDown(11);

Up and Down (1.3)_console_dump.txt

Native Browser JavaScript
>>> 0 1 2 1 0
0 1 2 3 4 5 6 7 8 9 10 11 10 9 8 7 6 5 4 3 2 1 0