prefault.test.ts•2.06 kB
import { expect, expectTypeOf, test } from "vitest";
import { z } from "zod/v4";
test("basic prefault", () => {
const a = z.prefault(z.string().trim(), " default ");
expect(a).toBeInstanceOf(z.ZodPrefault);
expect(a.parse(" asdf ")).toEqual("asdf");
expect(a.parse(undefined)).toEqual("default");
type inp = z.input<typeof a>;
expectTypeOf<inp>().toEqualTypeOf<string | undefined>();
type out = z.output<typeof a>;
expectTypeOf<out>().toEqualTypeOf<string>();
});
test("prefault inside object", () => {
// test optinality
const a = z.object({
name: z.string().optional(),
age: z.number().default(1234),
email: z.string().prefault("1234"),
});
type inp = z.input<typeof a>;
expectTypeOf<inp>().toEqualTypeOf<{
name?: string | undefined;
age?: number | undefined;
email?: string | undefined;
}>();
type out = z.output<typeof a>;
expectTypeOf<out>().toEqualTypeOf<{
name?: string | undefined;
age: number;
email: string;
}>();
});
test("object schema with prefault should return shallow clone", () => {
const schema = z
.object({
a: z.string(),
})
.default({ a: "x" });
const result1 = schema.parse(undefined);
const result2 = schema.parse(undefined);
expect(result1).not.toBe(result2);
expect(result1).toEqual(result2);
});
test("direction-aware prefault", () => {
const schema = z.string().prefault("hello");
// Forward direction (regular parse): prefault should be applied
expect(schema.parse(undefined)).toBe("hello");
// Reverse direction (encode): prefault should NOT be applied, undefined should fail validation
expect(z.safeEncode(schema, undefined as any)).toMatchInlineSnapshot(`
{
"error": [ZodError: [
{
"expected": "string",
"code": "invalid_type",
"path": [],
"message": "Invalid input: expected string, received undefined"
}
]],
"success": false,
}
`);
// But valid values should still work in reverse
expect(z.encode(schema, "world")).toBe("world");
});