add never props to safe parse return types (#3295)

Author: schicks

deno/lib/__tests__/safeparse.test.ts

@@ -8,13 +8,13 @@ const stringSchema = z.string();
 test("safeparse fail", () => {
   const safe = stringSchema.safeParse(12);
   expect(safe.success).toEqual(false);
-  expect((safe as any).error).toBeInstanceOf(z.ZodError);
+  expect(safe.error).toBeInstanceOf(z.ZodError);
 });
 
 test("safeparse pass", () => {
   const safe = stringSchema.safeParse("12");
   expect(safe.success).toEqual(true);
-  expect((safe as any).data).toEqual("12");
+  expect(safe.data).toEqual("12");
 });
 
 test("safeparse unexpected error", () => {

deno/lib/types.ts

@@ -144,8 +144,16 @@ function processCreateParams(params: RawCreateParams): ProcessedCreateParams {
   return { errorMap: customMap, description };
 }
 
-export type SafeParseSuccess<Output> = { success: true; data: Output };
-export type SafeParseError<Input> = { success: false; error: ZodError<Input> };
+export type SafeParseSuccess<Output> = {
+  success: true;
+  data: Output;
+  error?: never;
+};
+export type SafeParseError<Input> = {
+  success: false;
+  error: ZodError<Input>;
+  data?: never;
+};
 
 export type SafeParseReturnType<Input, Output> =
   | SafeParseSuccess<Output>

src/__tests__/safeparse.test.ts

@@ -7,13 +7,13 @@ const stringSchema = z.string();
 test("safeparse fail", () => {
   const safe = stringSchema.safeParse(12);
   expect(safe.success).toEqual(false);
-  expect((safe as any).error).toBeInstanceOf(z.ZodError);
+  expect(safe.error).toBeInstanceOf(z.ZodError);
 });
 
 test("safeparse pass", () => {
   const safe = stringSchema.safeParse("12");
   expect(safe.success).toEqual(true);
-  expect((safe as any).data).toEqual("12");
+  expect(safe.data).toEqual("12");
 });
 
 test("safeparse unexpected error", () => {

src/types.ts

@@ -144,8 +144,16 @@ function processCreateParams(params: RawCreateParams): ProcessedCreateParams {
   return { errorMap: customMap, description };
 }
 
-export type SafeParseSuccess<Output> = { success: true; data: Output };
-export type SafeParseError<Input> = { success: false; error: ZodError<Input> };
+export type SafeParseSuccess<Output> = {
+  success: true;
+  data: Output;
+  error?: never;
+};
+export type SafeParseError<Input> = {
+  success: false;
+  error: ZodError<Input>;
+  data?: never;
+};
 
 export type SafeParseReturnType<Input, Output> =
   | SafeParseSuccess<Output>