--- /dev/null
+function incrementListIndex(current, dir, opt) {
+ var len = opt.choices.realLength;
+ var shouldLoop = 'loop' in opt ? Boolean(opt.loop) : true;
+ if (dir === 'up') {
+ if (current > 0) {
+ return current - 1;
+ }
+ return shouldLoop ? len - 1 : current;
+ }
+ if (dir === 'down') {
+ if (current < len - 1) {
+ return current + 1;
+ }
+ return shouldLoop ? 0 : current;
+ }
+ throw new Error('dir must be up or down');
+}
+
+module.exports = incrementListIndex;