more random funcs

app/src/shared/utils.ts

@@ -19,4 +19,16 @@ export function rng(min: number, max = 0) {
     min = Math.ceil(min)
     max = Math.floor(max)
     return Math.floor(Math.random() * (max - min + 1)) + min
+}
+
+// randomElement([5, 7, 9]) #=> 7
+export function randomElement<T>(list: T[]): T | undefined {
+    if (!list.length) return
+    return list[rng(0, list.length - 1)]
+}
+
+// randomIndex([5, 7, 9]) #=> 1
+export function randomIndex<T>(list: T[]): number | undefined {
+    if (!list.length) return
+    return rng(0, list.length - 1)
 }