zod/src/v4/classic/tests/union.test.ts

TypeScript-first schema declaration and validation library with static type inference

import { expect, expectTypeOf, test } from "vitest";

import * as z from "zod/v4";

test("function parsing", () => {
  const schema = z.union([z.string().refine(() => false), z.number().refine(() => false)]);
  const result = schema.safeParse("asdf");
  expect(result.success).toEqual(false);
});

test("union 2", () => {
  const result = z.union([z.number(), z.string().refine(() => false)]).safeParse("a");
  expect(result.success).toEqual(false);
});

test("return valid over invalid", () => {
  const schema = z.union([
    z.object({
      email: z.string().email(),
    }),
    z.string(),
  ]);
  expect(schema.parse("asdf")).toEqual("asdf");
  expect(schema.parse({ email: "asdlkjf@lkajsdf.com" })).toEqual({
    email: "asdlkjf@lkajsdf.com",
  });
});

test("return errors from both union arms", () => {
  const result = z.union([z.number(), z.string().refine(() => false)]).safeParse("a");
  expect(result.success).toEqual(false);
  if (!result.success) {
    expect(result.error.issues).toMatchInlineSnapshot(`
      [
        {
          "code": "invalid_union",
          "errors": [
            [
              {
                "code": "invalid_type",
                "expected": "number",
                "message": "Invalid input: expected number, received string",
                "path": [],
              },
            ],
            [
              {
                "code": "custom",
                "message": "Invalid input",
                "path": [],
              },
            ],
          ],
          "message": "Invalid input",
          "path": [],
        },
      ]
    `);
  }
});

test("options getter", async () => {
  const union = z.union([z.string(), z.number()]);
  union.options[0].parse("asdf");
  union.options[1].parse(1234);
  await union.options[0].parseAsync("asdf");
  await union.options[1].parseAsync(1234);
});

test("readonly union", async () => {
  const options = [z.string(), z.number()] as const;
  const union = z.union(options);
  union.parse("asdf");
  union.parse(12);
});

test("union inferred types", () => {
  const test = z.object({}).or(z.array(z.object({})));

  type Test = z.output<typeof test>; // <— any
  expectTypeOf<Test>().toEqualTypeOf<Record<string, never> | Array<Record<string, never>>>();
});

test("union values", () => {
  const schema = z.union([z.literal("a"), z.literal("b"), z.literal("c")]);

  expect(schema._zod.values).toMatchInlineSnapshot(`
    Set {
      "a",
      "b",
      "c",
    }
  `);
});