split utils

utils/arrayUtils.js

@@ -0,0 +1,13 @@
+"use strict";
+// FMG utils related to arrays
+
+// return the last element of array
+function last(array) {
+  return array[array.length - 1];
+}
+
+// return array of values common for both array a and array b
+function common(a, b) {
+  const setB = new Set(b);
+  return [...new Set(a)].filter(a => setB.has(a));
+}