Bring back the utility belt

packages/utility-belt/index.d.ts

@@ -0,0 +1,7 @@
+export type RequireOnly<T, Keys extends keyof T = keyof T> = Partial<T> &
+  Required<Pick<T, Keys>>;
+export declare const isError: (error: unknown) => error is Error;
+export declare const getErrorMessage: (
+  error: unknown,
+  defaultMessage: string,
+) => string;