Fix CamelCaseKeys type (#78)

Author: nano72mkn

index.d.ts

@@ -66,16 +66,14 @@ type CamelCaseKeys<
 			]
 				? T[P]
 				: [Deep] extends [true]
-					? T[P] extends Record<string, any>
-						? CamelCaseKeys<
-						T[P],
-						Deep,
-						IsPascalCase,
-						Exclude,
-						StopPaths,
-						AppendPath<Path, P>
-						>
-						: T[P]
+					? CamelCaseKeys<
+					T[P],
+					Deep,
+					IsPascalCase,
+					Exclude,
+					StopPaths,
+					AppendPath<Path, P>
+					>
 					: T[P];
 		}
 		// Return anything else as-is.

index.test-d.ts

@@ -36,6 +36,26 @@ expectType<{fooBar: {fooBar: {fooBar: boolean}}}>(
 	)
 );
 
+interface ObjectOrUndefined {
+	foo_bar: {
+		foo_bar: {
+			foo_bar: boolean;
+		} | undefined;
+	};
+}
+
+const objectOrUndefined: ObjectOrUndefined = {
+	foo_bar: {
+		foo_bar: {
+			foo_bar: true
+		}
+	}
+};
+
+expectType<{fooBar: {fooBar: {fooBar: boolean} | undefined}}>(
+	camelcaseKeys(objectOrUndefined, {deep: true})
+);
+
 expectType<{FooBar: boolean}>(
 	camelcaseKeys({'foo-bar': true}, {pascalCase: true})
 );