feat: add MaybeNull validator

Author: akim-bow

src/type-system/index.ts

@@ -1,4 +1,4 @@
-import { Type, Kind } from '@sinclair/typebox'
+import { Type, Kind, Static } from '@sinclair/typebox'
 import type {
 	ArrayOptions,
 	DateOptions,
@@ -492,12 +492,21 @@ export const ElysiaType = {
 			})
 			.Encode((value) => value) as unknown as TUnsafe<File[]>,
 
+	/**
+	 * @deprecated Use MaybeNull instead which is OpenAPI 3.0 compliant. Will be removed in the next major release
+	 */
 	Nullable: <T extends TSchema>(schema: T, options?: SchemaOptions) =>
 		t.Union([schema, t.Null()], {
 			...options,
 			nullable: true
 		}),
 
+	MaybeNull: <T extends TSchema>(schema: T): TUnsafe<Static<T> | null> =>
+		Type.Unsafe({
+			...schema,
+			nullable: true,
+		}),
+
 	/**
 	 * Allow Optional, Nullable and Undefined
 	 */
@@ -660,6 +669,7 @@ t.Files = (arg) => {
 }
 
 t.Nullable = ElysiaType.Nullable
+t.MaybeNull = ElysiaType.MaybeNull
 t.MaybeEmpty = ElysiaType.MaybeEmpty
 t.Cookie = ElysiaType.Cookie
 t.Date = ElysiaType.Date

test/type-system/maybe-null.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it } from 'bun:test'
+import Elysia, { t } from '../../src'
+import { post } from '../utils'
+
+describe('TypeSystem - MaybeNull', () => {
+	it('OpenAPI compliant', () => {
+		const schema = t.MaybeNull(t.String());
+
+		expect(schema).toMatchObject({
+			type: "string",
+			nullable: true
+		});
+
+		const objSchema = t.Object({
+			name: t.MaybeNull(t.String())
+		});
+
+		expect(objSchema).toMatchObject({
+			type: "object",
+			properties: {
+				name: {
+					type: "string",
+					nullable: true
+				}
+			},
+		});
+	});
+
+	it('Validate', async () => {
+		const app = new Elysia().post('/', ({ body }) => body, {
+			body: t.Object({
+				name: t.Nullable(t.String())
+			})
+		})
+
+		const res1 = await app.handle(
+			post('/', {
+				name: '123'
+			})
+		)
+		expect(res1.status).toBe(200)
+		expect(await res1.json()).toEqual({ name: '123' })
+
+		const res2 = await app.handle(post('/', {
+			name: null
+		}))
+		expect(res2.status).toBe(200)
+		expect(await res2.json()).toEqual({ name: null })
+
+		const res3 = await app.handle(post('/', {}))
+		expect(res3.status).toBe(422)
+	});
+})