TypeBox Union Type Recognition Regression in Elysia 1.3.8 (t.Union)

[FahimMontasir]

What version of Elysia is running?

1.3.8

What platform is your computer?

Darwin 24.5.0 arm64 arm

What steps can reproduce the bug?

1. Create a simple Drizzle table schema
2. Generate TypeBox schemas using drizzle-typebox
3. Create a union schema with composite types using the generated schemas
4. Set up an Elysia route with this validation
5. Send valid data that matches the schema structure

Code snippet to reproduce:

import { Elysia, t } from "elysia";
import { createInsertSchema, createSelectSchema } from "drizzle-typebox";
import { pgTable, varchar, text, integer, boolean } from "drizzle-orm/pg-core";

// Simple Drizzle table
const usersTable = pgTable("users", {
  id: integer("id").primaryKey(),
  uid: varchar("uid", { length: 25 }).notNull(),
  username: varchar("username", { length: 50 }).notNull(),
  firstName: varchar("first_name", { length: 100 }),
  bio: text("bio"),
  isOnboarded: boolean("is_onboarded").default(false),
});

const userLanguagesTable = pgTable("user_languages", {
  id: integer("id").primaryKey(),
  userId: integer("user_id").notNull(),
  languageCode: varchar("language_code", { length: 10 }).notNull(),
  level: varchar("level", { length: 20 }),
});

// Generate TypeBox schemas
const UserSelectSchema = createSelectSchema(usersTable);
const UserLanguageSelectSchema = createSelectSchema(userLanguagesTable);

// Problematic union schema with composite + drizzle schemas
const UserProfileSchema = t.Union([
  t.Composite([
    t.Omit(UserSelectSchema, ["id"]),
    t.Object({
      languages: t.Union([
        t.Array(t.Omit(UserLanguageSelectSchema, ["id", "userId"])),
        t.Null(),
      ]),
    }),
  ]),
  t.Null(),
]);

What is the expected behavior?

The validation should pass and return:

{
  "success": true,
  "data": {
    "uid": "user_123",
    "username": "testuser",
    "firstName": "John",
    "bio": "Hello world",
    "isOnboarded": true,
    "languages": [
      { "languageCode": "en", "level": "advanced" }
    ]
  }
}

What do you see instead?

Validation fails with a error:

{
 type: 62,
schema: {
     [Symbol(TypeBox.Kind)]: "Union",
     anyOf: [ ....
message: "Expected union value",
  errors: [
  ValueErrorIterator {
  iterator: {},
    [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
     }, ValueErrorIterator {
       iterator: {},
       [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
    }, ValueErrorIterator {
      iterator: {},
       [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
     }
   ],
:summary: "Value should be one of 'object', 'undefined', 'null'",
}

Additional information

Version Details:

• Broken: Elysia 1.3.8
• Working: Elysia 1.3.1
• drizzle-typebox: 0.3.3

Have you try removing the node_modules and bun.lockb and try again yet?

yes

[SaltyAom]

I think I might be missing something as I couldn't reproduce with the following code:

import { Elysia, t } from 'elysia'
import { createInsertSchema, createSelectSchema } from 'drizzle-typebox'
import { pgTable, varchar, text, integer, boolean } from 'drizzle-orm/pg-core'

// Simple Drizzle table
const usersTable = pgTable('users', {
	id: integer('id').primaryKey(),
	uid: varchar('uid', { length: 25 }).notNull(),
	username: varchar('username', { length: 50 }).notNull(),
	firstName: varchar('first_name', { length: 100 }),
	bio: text('bio'),
	isOnboarded: boolean('is_onboarded').default(false)
})

const userLanguagesTable = pgTable('user_languages', {
	id: integer('id').primaryKey(),
	userId: integer('user_id').notNull(),
	languageCode: varchar('language_code', { length: 10 }).notNull(),
	level: varchar('level', { length: 20 })
})

// Generate TypeBox schemas
const UserSelectSchema = createSelectSchema(usersTable)
const UserLanguageSelectSchema = createSelectSchema(userLanguagesTable)

// Problematic union schema with composite + drizzle schemas
const UserProfileSchema = t.Union([
	t.Composite([
		t.Omit(UserSelectSchema, ['id']),
		t.Object({
			languages: t.Union([
				t.Array(t.Omit(UserLanguageSelectSchema, ['id', 'userId'])),
				t.Null()
			])
		})
	]),
	t.Null()
])

const app = new Elysia()
	.get(
		'',
		() => {
			return {
				uid: 'user_123',
				username: 'testuser',
				firstName: 'John',
				bio: 'Hello world',
				isOnboarded: true,
				languages: [{ languageCode: 'en', level: 'advanced' }]
			}
		},
		{
			response: UserProfileSchema
		}
	)
	.listen(3000)

app.handle(new Request('http://localhost'))
	.then((x) => x.json())
	.then(console.log)

[SohelIslamImran]

Screen.Recording.2025-08-17.at.11.30.32.PM-1.mp4

@SaltyAom Here is the issue after upgrading to Elysia 1.3.8

[SohelIslamImran]

The t.Union has many issues. It also doesn't transform number Literal and throws error.. But t.Number seems transform the value.

const PageSchema = t.Object({
  page: t.Numeric({ minimum: 1, default: 1 }),
  limit: t.Numeric({ minimum: 1, maximum: 100, default: 20 }),
  duration: t.Union([
    t.Literal(15),
    t.Literal(30),
    t.Literal(45),
    t.Literal(60),
  ]),
});

[VALIDATION ERROR]  {
   type: 62,
   schema: {
     [Symbol(TypeBox.Kind)]: "Union",
     anyOf: [
       [Object ...], [Object ...], [Object ...], [Object ...]
     ],
   },
   path: "/duration",
   value: "30",
   message: "Expected union value",
   errors: [
     ValueErrorIterator {
       iterator: {},
       [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
     }, ValueErrorIterator {
       iterator: {},
       [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
     }, ValueErrorIterator {
       iterator: {},
       [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
     }, ValueErrorIterator {
       iterator: {},
       [Symbol(Symbol.iterator)]: [Function],
       First: [Function: First],
     }
   ],
   summary: "Property 'duration' should be one of: 'number', 'number', 'number', 'number'",
 }

[dodas]

This is blocking our migration to latest Elysia.