feat: application of unbranding type to types not applied

src/types/DeepDateToString.ts

@@ -1,21 +1,23 @@
+import { DeepStrictUnbrand } from './DeepStrictUnbrand';
+
 /**
  * A utility type that recursively converts all `Date` types within a nested object or array to `string`.
  *
  * - If `T` is an array of objects, the type processes each element recursively.
  * - If `T` is a `Date`, it is converted to `string`.
  * - If `T` is an object, each key is checked recursively for `Date` types or nested objects.
  */
-export type DeepDateToString<T> =
-  T extends Array<infer I extends object>
+export type DeepDateToString<T extends object> =
+  DeepStrictUnbrand<T> extends Array<infer I extends object>
     ? Array<DeepDateToString<I>>
     : T extends Date
       ? string
       : {
           [K in keyof T]: T[K] extends infer I
             ? I extends Date
               ? string
-              : I extends object
-                ? DeepDateToString<I>
+              : DeepStrictUnbrand<I> extends object
+                ? DeepDateToString<DeepStrictUnbrand<I>>
                 : I
             : never;
         };

src/types/GetStrictObjectLastKeys.ts

@@ -1,3 +1,4 @@
+import { DeepStrictUnbrand } from './DeepStrictUnbrand';
 import type { IsAny } from './IsAny';
 import type { IsUnion } from './IsUnion';
 import type { ValueType } from './ValueType';
@@ -53,8 +54,8 @@ export type DeepStrictObjectLastKeys<
   },
   P extends keyof T = keyof T,
 > =
-  T extends Array<infer Element>
+  DeepStrictUnbrand<T> extends Array<infer Element>
     ? Element extends object
-      ? `${Joiner['array']}.${DeepStrictObjectLastKeys<Element, Joiner>}`
+      ? `${Joiner['array']}.${DeepStrictObjectLastKeys<DeepStrictUnbrand<Element>, Joiner>}`
       : `${Joiner['array']}.${keyof Element extends string ? keyof Element : never}`
-    : __DeepStrictObjectKeys<T, Joiner, P>;
+    : __DeepStrictObjectKeys<DeepStrictUnbrand<T>, Joiner, Extract<P, keyof DeepStrictUnbrand<T>>>;

test/DeepDateToString.ts

@@ -1,7 +1,7 @@
+import { ok } from 'node:assert';
+import test from 'node:test';
 import typia from 'typia';
 import { DeepDateToString, Equal } from '../src';
-import test from 'node:test';
-import { ok } from 'node:assert';
 
 test('If the prop type of an object is string | Date', () => {
   type Question = DeepDateToString<{ prop: string | Date }>;
@@ -37,3 +37,10 @@ test('If the prop type of an object is symbol | Date', () => {
 
   ok(typia.random<Answer>());
 });
+
+test('If the prop type of an object is symbol | (string & {}) | Date', () => {
+  type Question = DeepDateToString<{ prop: symbol | (string & {}) | Date }>;
+  type Answer = Equal<Question, { prop: symbol | string }>;
+
+  ok(typia.random<Answer>());
+});