move helpers to new workspace folder

packages/helpers/omit.ts

@@ -0,0 +1,13 @@
+export function omit<Subject extends object, Key extends PropertyKey>(
+  subject: Subject,
+  keys: Key[],
+  // hack: using a conditional type preserves union types
+): Subject extends any ? Omit<Subject, Key> : never {
+  const result: any = {}
+  for (const key in subject) {
+    if (!keys.includes(key as unknown as Key)) {
+      result[key] = subject[key]
+    }
+  }
+  return result
+}