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x/zod/__tests__/discriminated-unions.test.ts

TypeScript-first schema validation with static type inference
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// @ts-ignore TS6133import { expect } from "https://deno.land/x/expect@v0.2.6/mod.ts";const test = Deno.test;
import * as z from "../index.ts";
test("valid", () => { expect( z .discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z.string() }), z.object({ type: z.literal("b"), b: z.string() }), ]) .parse({ type: "a", a: "abc" }) ).toEqual({ type: "a", a: "abc" });});
test("valid - discriminator value of various primitive types", () => { const schema = z.discriminatedUnion("type", [ z.object({ type: z.literal("1"), val: z.literal(1) }), z.object({ type: z.literal(1), val: z.literal(2) }), z.object({ type: z.literal(BigInt(1)), val: z.literal(3) }), z.object({ type: z.literal("true"), val: z.literal(4) }), z.object({ type: z.literal(true), val: z.literal(5) }), z.object({ type: z.literal("null"), val: z.literal(6) }), z.object({ type: z.literal(null), val: z.literal(7) }), z.object({ type: z.literal("undefined"), val: z.literal(8) }), z.object({ type: z.literal(undefined), val: z.literal(9) }), z.object({ type: z.literal("transform"), val: z.literal(10) }), z.object({ type: z.literal("refine"), val: z.literal(11) }), z.object({ type: z.literal("superRefine"), val: z.literal(12) }), ]);
expect(schema.parse({ type: "1", val: 1 })).toEqual({ type: "1", val: 1 }); expect(schema.parse({ type: 1, val: 2 })).toEqual({ type: 1, val: 2 }); expect(schema.parse({ type: BigInt(1), val: 3 })).toEqual({ type: BigInt(1), val: 3, }); expect(schema.parse({ type: "true", val: 4 })).toEqual({ type: "true", val: 4, }); expect(schema.parse({ type: true, val: 5 })).toEqual({ type: true, val: 5, }); expect(schema.parse({ type: "null", val: 6 })).toEqual({ type: "null", val: 6, }); expect(schema.parse({ type: null, val: 7 })).toEqual({ type: null, val: 7, }); expect(schema.parse({ type: "undefined", val: 8 })).toEqual({ type: "undefined", val: 8, }); expect(schema.parse({ type: undefined, val: 9 })).toEqual({ type: undefined, val: 9, });});
test("invalid - null", () => { try { z.discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z.string() }), z.object({ type: z.literal("b"), b: z.string() }), ]).parse(null); throw new Error(); } catch (e: any) { expect(JSON.parse(e.message)).toEqual([ { code: z.ZodIssueCode.invalid_type, expected: z.ZodParsedType.object, message: "Expected object, received null", received: z.ZodParsedType.null, path: [], }, ]); }});
test("invalid discriminator value", () => { try { z.discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z.string() }), z.object({ type: z.literal("b"), b: z.string() }), ]).parse({ type: "x", a: "abc" }); throw new Error(); } catch (e: any) { expect(JSON.parse(e.message)).toEqual([ { code: z.ZodIssueCode.invalid_union_discriminator, options: ["a", "b"], message: "Invalid discriminator value. Expected 'a' | 'b'", path: ["type"], }, ]); }});
test("valid discriminator value, invalid data", () => { try { z.discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z.string() }), z.object({ type: z.literal("b"), b: z.string() }), ]).parse({ type: "a", b: "abc" }); throw new Error(); } catch (e: any) { expect(JSON.parse(e.message)).toEqual([ { code: z.ZodIssueCode.invalid_type, expected: z.ZodParsedType.string, message: "Required", path: ["a"], received: z.ZodParsedType.undefined, }, ]); }});
test("wrong schema - missing discriminator", () => { try { z.discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z.string() }), z.object({ b: z.string() }) as any, ]); throw new Error(); } catch (e: any) { expect(e.message.includes("could not be extracted")).toBe(true); }});
test("wrong schema - duplicate discriminator values", () => { try { z.discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z.string() }), z.object({ type: z.literal("a"), b: z.string() }), ]); throw new Error(); } catch (e: any) { expect(e.message.includes("has duplicate value")).toEqual(true); }});
test("async - valid", async () => { expect( await z .discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z .string() .refine(async () => true) .transform(async (val) => Number(val)), }), z.object({ type: z.literal("b"), b: z.string(), }), ]) .parseAsync({ type: "a", a: "1" }) ).toEqual({ type: "a", a: 1 });});
test("async - invalid", async () => { try { await z .discriminatedUnion("type", [ z.object({ type: z.literal("a"), a: z .string() .refine(async () => true) .transform(async (val) => val), }), z.object({ type: z.literal("b"), b: z.string(), }), ]) .parseAsync({ type: "a", a: 1 }); throw new Error(); } catch (e: any) { expect(JSON.parse(e.message)).toEqual([ { code: "invalid_type", expected: "string", received: "number", path: ["a"], message: "Expected string, received number", }, ]); }});
test("valid - literals with .default or .preprocess", () => { const schema = z.discriminatedUnion("type", [ z.object({ type: z.literal("foo").default("foo"), a: z.string(), }), z.object({ type: z.literal("custom"), method: z.string(), }), z.object({ type: z.preprocess((val) => String(val), z.literal("bar")), c: z.string(), }), ]); expect(schema.parse({ type: "foo", a: "foo" })).toEqual({ type: "foo", a: "foo", });});
test("enum and nativeEnum", () => { enum MyEnum { d, e = "e", }
const schema = z.discriminatedUnion("key", [ z.object({ key: z.literal("a"), // Add other properties specific to this option }), z.object({ key: z.enum(["b", "c"]), // Add other properties specific to this option }), z.object({ key: z.nativeEnum(MyEnum), // Add other properties specific to this option }), ]);
type schema = z.infer<typeof schema>;
schema.parse({ key: "a" }); schema.parse({ key: "b" }); schema.parse({ key: "c" }); schema.parse({ key: MyEnum.d }); schema.parse({ key: MyEnum.e }); schema.parse({ key: "e" });});
test("branded", () => { const schema = z.discriminatedUnion("key", [ z.object({ key: z.literal("a"), // Add other properties specific to this option }), z.object({ key: z.literal("b").brand("asdfaf"), // Add other properties specific to this option }), ]);
type schema = z.infer<typeof schema>;
schema.parse({ key: "a" }); schema.parse({ key: "b" }); expect(() => { schema.parse({ key: "c" }); }).toThrow();});
test("optional and nullable", () => { const schema = z.discriminatedUnion("key", [ z.object({ key: z.literal("a").optional(), a: z.literal(true), }), z.object({ key: z.literal("b").nullable(), b: z.literal(true), // Add other properties specific to this option }), ]);
type schema = z.infer<typeof schema>; z.util.assertEqual< schema, { key?: "a" | undefined; a: true } | { key: "b" | null; b: true } >(true);
schema.parse({ key: "a", a: true }); schema.parse({ key: undefined, a: true }); schema.parse({ key: "b", b: true }); schema.parse({ key: null, b: true }); expect(() => { schema.parse({ key: null, a: true }); }).toThrow(); expect(() => { schema.parse({ key: "b", a: true }); }).toThrow();
const value = schema.parse({ key: null, b: true });
if (!("key" in value)) value.a; if (value.key === undefined) value.a; if (value.key === "a") value.a; if (value.key === "b") value.b; if (value.key === null) value.b;});