add cmpRef util

frontend/app/utils/cmpRef.ts

@@ -0,0 +1,13 @@
+import isEqual from 'lodash/isEqual';
+
+/**
+ * Deeply compares two entities,
+ * and if they are equal, then first entity
+ * will be returned
+ *
+ * Useful when we deal with react objects
+ */
+export function cmpRef<T>(a: T, b: T): T {
+  if (isEqual(a, b)) return a;
+  return b;
+}