feat: support output data validation (#250)

This PR adds the `outputSchema` method to allow for optional validation
of the action's return value.

re #245

README.md

@@ -17,7 +17,7 @@ https://github.com/TheEdoRan/next-safe-action/assets/1337629/664eb3ee-92f3-4d4a-
 - ✅ End-to-end type safety
 - ✅ Form Actions support
 - ✅ Powerful middleware system
-- ✅ Input validation using multiple validation libraries
+- ✅ Input/output validation using multiple validation libraries
 - ✅ Advanced server error handling
 - ✅ Optimistic updates
 

package.json

@@ -36,7 +36,7 @@
 		"cz-conventional-changelog": "^3.3.0",
 		"husky": "^9.0.11",
 		"is-ci": "^3.0.1",
-		"turbo": "^2.0.14"
+		"turbo": "^2.1.0"
 	},
 	"packageManager": "[email protected]+sha512.60c18acd138bff695d339be6ad13f7e936eea6745660d4cc4a776d5247c540d0edee1a563695c183a66eb917ef88f2b4feb1fc25f32a7adcadc7aaf3438e99c1"
 }

packages/next-safe-action/README.md

@@ -17,7 +17,7 @@ https://github.com/TheEdoRan/next-safe-action/assets/1337629/664eb3ee-92f3-4d4a-
 - ✅ End-to-end type safety
 - ✅ Form Actions support
 - ✅ Powerful middleware system
-- ✅ Input validation using multiple validation libraries
+- ✅ Input/output validation using multiple validation libraries
 - ✅ Advanced server error handling
 - ✅ Optimistic updates
 

packages/next-safe-action/src/__tests__/happy-path.test.ts

@@ -38,14 +38,17 @@ test("action with no input schema and return data gives back an object with corr
 	assert.deepStrictEqual(actualResult, expectedResult);
 });
 
-test("action with input schema and return data gives back an object with correct `data`", async () => {
+test("action with input, output schema and return data gives back an object with correct `data`", async () => {
 	const userId = "ed6f5b84-6bca-4d01-9a51-c3d0c49a7996";
 
-	const action = ac.schema(z.object({ userId: z.string().uuid() })).action(async ({ parsedInput }) => {
-		return {
-			userId: parsedInput.userId,
-		};
-	});
+	const action = ac
+		.schema(z.object({ userId: z.string().uuid() }))
+		.outputSchema(z.object({ userId: z.string() }))
+		.action(async ({ parsedInput }) => {
+			return {
+				userId: parsedInput.userId,
+			};
+		});
 
 	const actualResult = await action({ userId });
 
@@ -80,13 +83,14 @@ test("action with input schema passed via async function and return data gives b
 	assert.deepStrictEqual(actualResult, expectedResult);
 });
 
-test("action with input schema extended via async function and return data gives back an object with correct `data`", async () => {
+test("action with input schema extended via async function, ouput schema and return data gives back an object with correct `data`", async () => {
 	const userId = "ed6f5b84-6bca-4d01-9a51-c3d0c49a7996";
 	const password = "password";
 
 	const action = ac
 		.schema(z.object({ password: z.string() }))
 		.schema(async (prevSchema) => prevSchema.extend({ userId: z.string().uuid() }))
+		.outputSchema(z.object({ userId: z.string(), password: z.string() }))
 		.action(async ({ parsedInput }) => {
 			return {
 				userId: parsedInput.userId,
@@ -106,12 +110,13 @@ test("action with input schema extended via async function and return data gives
 	assert.deepStrictEqual(actualResult, expectedResult);
 });
 
-test("action with no input schema, bind args input schemas and return data gives back an object with correct `data`", async () => {
+test("action with no input schema, with bind args input schemas, output schema and return data gives back an object with correct `data`", async () => {
 	const username = "johndoe";
 	const age = 30;
 
 	const action = ac
 		.bindArgsSchemas<[username: z.ZodString, age: z.ZodNumber]>([z.string(), z.number()])
+		.outputSchema(z.object({ username: z.string(), age: z.number() }))
 		.action(async ({ bindArgsParsedInputs: [username, age] }) => {
 			return {
 				username,
@@ -131,14 +136,15 @@ test("action with no input schema, bind args input schemas and return data gives
 	assert.deepStrictEqual(actualResult, expectedResult);
 });
 
-test("action with input schema, bind args input schemas and return data gives back an object with correct `data`", async () => {
+test("action with input schema, bind args input schemas, output schema and return data gives back an object with correct `data`", async () => {
 	const userId = "ed6f5b84-6bca-4d01-9a51-c3d0c49a7996";
 	const username = "johndoe";
 	const age = 30;
 
 	const action = ac
 		.schema(z.object({ userId: z.string().uuid() }))
 		.bindArgsSchemas<[username: z.ZodString, age: z.ZodNumber]>([z.string(), z.number()])
+		.outputSchema(z.object({ userId: z.string(), username: z.string(), age: z.number() }))
 		.action(async ({ parsedInput, bindArgsParsedInputs: [username, age] }) => {
 			return {
 				userId: parsedInput.userId,

packages/next-safe-action/src/__tests__/validation-errors.test.ts

@@ -3,8 +3,16 @@
 import assert from "node:assert";
 import { test } from "node:test";
 import { z } from "zod";
-import { createSafeActionClient, flattenValidationErrors, formatValidationErrors, returnValidationErrors } from "..";
+import type { ValidationErrors } from "..";
+import {
+	createSafeActionClient,
+	DEFAULT_SERVER_ERROR_MESSAGE,
+	flattenValidationErrors,
+	formatValidationErrors,
+	returnValidationErrors,
+} from "..";
 import { zodAdapter } from "../adapters/zod";
+import { ActionOutputDataValidationError } from "../validation-errors";
 
 // Default client tests.
 
@@ -144,6 +152,58 @@ test("action with invalid input gives back an object with correct `validationErr
 	assert.deepStrictEqual(actualResult, expectedResult);
 });
 
+test("action with invalid output data returns the default `serverError`", async () => {
+	const action = dac.outputSchema(z.object({ result: z.string().min(3) })).action(async () => {
+		return {
+			result: "ok",
+		};
+	});
+
+	const actualResult = await action();
+
+	const expectedResult = {
+		serverError: DEFAULT_SERVER_ERROR_MESSAGE,
+	};
+
+	assert.deepStrictEqual(actualResult, expectedResult);
+});
+
+test("action with invalid output data throws an error of the correct type", async () => {
+	const tac = createSafeActionClient({
+		validationAdapter: zodAdapter(),
+		handleReturnedServerError: (e) => {
+			throw e;
+		},
+	});
+
+	const outputSchema = z.object({ result: z.string().min(3) });
+
+	const action = tac.outputSchema(outputSchema).action(async () => {
+		return {
+			result: "ok",
+		};
+	});
+
+	const expectedResult = {
+		serverError: "String must contain at least 3 character(s)",
+	};
+
+	const actualResult = {
+		serverError: "",
+	};
+
+	try {
+		await action();
+	} catch (e) {
+		if (e instanceof ActionOutputDataValidationError) {
+			actualResult.serverError =
+				(e.validationErrors as ValidationErrors<typeof outputSchema>).result?._errors?.[0] ?? "";
+		}
+	}
+
+	assert.deepStrictEqual(actualResult, expectedResult);
+});
+
 // Formatted shape tests (same as default).
 
 const foac = createSafeActionClient({