Add support for dynamic values to withDefault

library/CHANGELOG.md

@@ -7,9 +7,10 @@ All notable changes to the library will be documented in this file.
 > Note: The library has been revised and refactored. There is a migration guide in the [release notes](https://github.com/fabian-hiller/valibot/releases/tag/vX.X.X).
 
 - Add `getPipeInfo`, `getPathInfo` and `getIssue` util (pull request #46, #92, #93)
-- Add support for `boolean`, `bigint` and `symbol` to `literal` (pull request #102)
 - Add `fallback` and `fallbackAsync` method (pull request #103)
-- Expand `flatten` so that issues are also accepted as first argument
+- Add support for `boolean`, `bigint` and `symbol` to `literal` schema (pull request #102)
+- Add support for dynamic values to `withDefault` method
+- Expand `flatten` method so that issues are also accepted as first argument
 - Change return type of `safeParse` and `safeParseAsync` method
 - Change error handling and refactor library to improve performance
 - Rename `.parse` to `._parse` and `.types` to `._types` to mark it as internal API

library/src/methods/withDefault/withDefault.ts

@@ -10,7 +10,7 @@ import type { BaseSchema, BaseSchemaAsync, Input } from '../../types.ts';
  */
 export function withDefault<TSchema extends BaseSchema | BaseSchemaAsync>(
   schema: TSchema,
-  value: Input<TSchema>
+  value: Input<TSchema> | (() => Input<TSchema>)
 ): TSchema {
   return {
     ...schema,
@@ -24,7 +24,14 @@ export function withDefault<TSchema extends BaseSchema | BaseSchemaAsync>(
      * @returns The parsed output.
      */
     _parse(input, info) {
-      return schema._parse(input === undefined ? value : input, info);
+      return schema._parse(
+        input === undefined
+          ? typeof value === 'function'
+            ? (value as () => Input<TSchema>)()
+            : value
+          : input,
+        info
+      );
     },
   };
 }