fix: it should throws an error when fake z.never (#201)

Co-authored-by: Ernest <>

Author: soc221b

README.md

@@ -41,7 +41,7 @@
   - ✅ numeric enums
   - ✅ string enums
   - ✅ const enums
-- ✅ z.never: return `undefined`
+- ✅ z.never: always throws an error
 - ✅ z.null
 - ✅ z.nullable
 - z.number
@@ -164,7 +164,6 @@ const schema = z.object({
   }),
   any: z.any(),
   unknown: z.unknown(),
-  // never: z.never(), // should not use its return value
   literal: z.literal('tuna'),
   strings: z.object({
     max: z.string().max(5),

src/zod-never-faker.ts

@@ -3,7 +3,7 @@ import { ZodTypeFaker } from './zod-type-faker'
 
 export class ZodNeverFaker extends ZodTypeFaker<z.ZodNever> {
   fake(): z.infer<z.ZodNever> {
-    return void 0 as never
+    throw Error()
   }
 
   static create(schema: z.ZodNever): ZodNeverFaker {

tests/integration.test.ts

@@ -40,7 +40,7 @@ testMultipleTimes('integration', async () => {
     }),
     any: z.any(),
     unknown: z.unknown(),
-    // never: z.never(), // should not use its return value
+    // never: z.never(), // always throws an error
     literal: z.literal('tuna'),
     strings: z.object({
       max: z.string().max(5),

tests/zod-never-faker.test.ts

@@ -31,8 +31,8 @@ test('ZodNeverFaker.fake should return never type', () => {
   expectType<TypeEqual<ReturnType<typeof faker.fake>, never>>(true)
 })
 
-test('ZodNullFaker.fake should return a data (but should not be used)', () => {
+test('ZodNullFaker.fake should throw an error', () => {
   const schema = z.never()
   const faker = zodNeverFaker(schema)
-  expect(() => faker.fake()).not.toThrow()
+  expect(() => faker.fake()).toThrow()
 })