refactor: make library backwards compatible with Next.js < 15.1 (#310)

Code in this PR bundles internal framework error handling (rethrown
navigation errors) to make next-safe-action compatible with both newer
and older Next.js versions.

packages/next-safe-action/package.json

@@ -91,9 +91,9 @@
 	},
 	"peerDependencies": {
 		"@sinclair/typebox": ">= 0.33.3",
-		"next": ">= 15.1.0",
-		"react": ">= 19.0.0",
-		"react-dom": ">= 19.0.0",
+		"next": ">= 14.0.0",
+		"react": ">= 18.2.0",
+		"react-dom": ">= 18.2.0",
 		"valibot": ">= 0.36.0",
 		"yup": ">= 1.0.0",
 		"zod": ">= 3.0.0"

packages/next-safe-action/src/action-builder.ts

@@ -13,15 +13,13 @@ import type {
 	StateServerCodeFn,
 } from "./index.types";
 import {
-	DEFAULT_SERVER_ERROR_MESSAGE,
-	isError,
 	isForbiddenError,
 	isFrameworkError,
 	isNotFoundError,
 	isRedirectError,
 	isUnauthorizedError,
-	winningBoolean,
-} from "./utils";
+} from "./next/errors";
+import { DEFAULT_SERVER_ERROR_MESSAGE, isError, winningBoolean } from "./utils";
 import {
 	ActionMetadataValidationError,
 	ActionOutputDataValidationError,

packages/next-safe-action/src/next/errors/bailout-to-csr.ts

@@ -0,0 +1,22 @@
+// Comes from https://github.com/vercel/next.js/blob/canary/packages/next/src/shared/lib/lazy-dynamic/bailout-to-csr.ts
+
+// This has to be a shared module which is shared between client component error boundary and dynamic component
+const BAILOUT_TO_CSR = "BAILOUT_TO_CLIENT_SIDE_RENDERING";
+
+/** An error that should be thrown when we want to bail out to client-side rendering. */
+class BailoutToCSRError extends Error {
+	public readonly digest = BAILOUT_TO_CSR;
+
+	constructor(public readonly reason: string) {
+		super(`Bail out to client-side rendering: ${reason}`);
+	}
+}
+
+/** Checks if a passed argument is an error that is thrown if we want to bail out to client-side rendering. */
+export function isBailoutToCSRError(err: unknown): err is BailoutToCSRError {
+	if (typeof err !== "object" || err === null || !("digest" in err)) {
+		return false;
+	}
+
+	return err.digest === BAILOUT_TO_CSR;
+}

packages/next-safe-action/src/next/errors/dynamic-usage.ts

@@ -0,0 +1,45 @@
+// Comes from https://github.com/vercel/next.js/blob/canary/packages/next/src/export/helpers/is-dynamic-usage-error.ts
+
+import { isBailoutToCSRError } from "./bailout-to-csr";
+import { isNextRouterError } from "./router";
+
+const DYNAMIC_ERROR_CODE = "DYNAMIC_SERVER_USAGE";
+
+class DynamicServerError extends Error {
+	digest: typeof DYNAMIC_ERROR_CODE = DYNAMIC_ERROR_CODE;
+
+	constructor(public readonly description: string) {
+		super(`Dynamic server usage: ${description}`);
+	}
+}
+
+function isDynamicServerError(err: unknown): err is DynamicServerError {
+	if (typeof err !== "object" || err === null || !("digest" in err) || typeof err.digest !== "string") {
+		return false;
+	}
+
+	return err.digest === DYNAMIC_ERROR_CODE;
+}
+
+function isDynamicPostponeReason(reason: string) {
+	return (
+		reason.includes("needs to bail out of prerendering at this point because it used") &&
+		reason.includes("Learn more: https://nextjs.org/docs/messages/ppr-caught-error")
+	);
+}
+
+function isDynamicPostpone(err: unknown) {
+	if (
+		typeof err === "object" &&
+		err !== null &&
+		// eslint-disable-next-line
+		typeof (err as any).message === "string"
+	) {
+		// eslint-disable-next-line
+		return isDynamicPostponeReason((err as any).message);
+	}
+	return false;
+}
+
+export const isDynamicUsageError = (err: unknown) =>
+	isDynamicServerError(err) || isBailoutToCSRError(err) || isNextRouterError(err) || isDynamicPostpone(err);

packages/next-safe-action/src/next/errors/http-access-fallback.ts

@@ -0,0 +1,36 @@
+// Comes from https://github.com/vercel/next.js/blob/canary/packages/next/src/client/components/http-access-fallback/http-access-fallback.ts
+
+const HTTPAccessErrorStatus = {
+	NOT_FOUND: 404,
+	FORBIDDEN: 403,
+	UNAUTHORIZED: 401,
+};
+
+const ALLOWED_CODES = new Set(Object.values(HTTPAccessErrorStatus));
+
+const HTTP_ERROR_FALLBACK_ERROR_CODE = "NEXT_HTTP_ERROR_FALLBACK";
+
+export type HTTPAccessFallbackError = Error & {
+	digest: `${typeof HTTP_ERROR_FALLBACK_ERROR_CODE};${string}`;
+};
+
+/**
+ * Checks an error to determine if it's an error generated by
+ * the HTTP navigation APIs `notFound()`, `forbidden()` or `unauthorized()`.
+ *
+ * @param error the error that may reference a HTTP access error
+ * @returns true if the error is a HTTP access error
+ */
+export function isHTTPAccessFallbackError(error: unknown): error is HTTPAccessFallbackError {
+	if (typeof error !== "object" || error === null || !("digest" in error) || typeof error.digest !== "string") {
+		return false;
+	}
+	const [prefix, httpStatus] = error.digest.split(";");
+
+	return prefix === HTTP_ERROR_FALLBACK_ERROR_CODE && ALLOWED_CODES.has(Number(httpStatus));
+}
+
+export function getAccessFallbackHTTPStatus(error: HTTPAccessFallbackError): number {
+	const httpStatus = error.digest.split(";")[1];
+	return Number(httpStatus);
+}

packages/next-safe-action/src/next/errors/index.ts

@@ -0,0 +1,28 @@
+import { isBailoutToCSRError } from "./bailout-to-csr";
+import { isDynamicUsageError } from "./dynamic-usage";
+import {
+	getAccessFallbackHTTPStatus,
+	isHTTPAccessFallbackError,
+	type HTTPAccessFallbackError,
+} from "./http-access-fallback";
+import { isPostpone } from "./postpone";
+import { isNextRouterError } from "./router";
+
+export function isNotFoundError(error: unknown): error is HTTPAccessFallbackError {
+	return isHTTPAccessFallbackError(error) && getAccessFallbackHTTPStatus(error) === 404;
+}
+
+export function isForbiddenError(error: unknown): error is HTTPAccessFallbackError {
+	return isHTTPAccessFallbackError(error) && getAccessFallbackHTTPStatus(error) === 403;
+}
+
+export function isUnauthorizedError(error: unknown): error is HTTPAccessFallbackError {
+	return isHTTPAccessFallbackError(error) && getAccessFallbackHTTPStatus(error) === 401;
+}
+
+// Next.js error handling
+export function isFrameworkError(error: unknown): error is Error {
+	return isNextRouterError(error) || isBailoutToCSRError(error) || isDynamicUsageError(error) || isPostpone(error);
+}
+
+export { isRedirectError } from "./redirect";

packages/next-safe-action/src/next/errors/postpone.ts

@@ -0,0 +1,12 @@
+// Comes from https://github.com/vercel/next.js/blob/canary/packages/next/src/server/lib/router-utils/is-postpone.ts
+
+const REACT_POSTPONE_TYPE: symbol = Symbol.for("react.postpone");
+
+export function isPostpone(error: any): boolean {
+	return (
+		typeof error === "object" &&
+		error !== null &&
+		// eslint-disable-next-line
+		error.$$typeof === REACT_POSTPONE_TYPE
+	);
+}

packages/next-safe-action/src/next/errors/redirect.ts

@@ -0,0 +1,46 @@
+// Comes from: https://github.com/vercel/next.js/blob/canary/packages/next/src/client/components/redirect-error.ts
+
+enum RedirectStatusCode {
+	SeeOther = 303,
+	TemporaryRedirect = 307,
+	PermanentRedirect = 308,
+}
+
+const REDIRECT_ERROR_CODE = "NEXT_REDIRECT";
+
+enum RedirectType {
+	push = "push",
+	replace = "replace",
+}
+
+export type RedirectError = Error & {
+	digest: `${typeof REDIRECT_ERROR_CODE};${RedirectType};${string};${RedirectStatusCode};`;
+};
+
+/**
+ * Checks an error to determine if it's an error generated by the
+ * `redirect(url)` helper.
+ *
+ * @param error the error that may reference a redirect error
+ * @returns true if the error is a redirect error
+ */
+export function isRedirectError(error: unknown): error is RedirectError {
+	if (typeof error !== "object" || error === null || !("digest" in error) || typeof error.digest !== "string") {
+		return false;
+	}
+
+	const digest = error.digest.split(";");
+	const [errorCode, type] = digest;
+	const destination = digest.slice(2, -2).join(";");
+	const status = digest.at(-2);
+
+	const statusCode = Number(status);
+
+	return (
+		errorCode === REDIRECT_ERROR_CODE &&
+		(type === "replace" || type === "push") &&
+		typeof destination === "string" &&
+		!isNaN(statusCode) &&
+		statusCode in RedirectStatusCode
+	);
+}

packages/next-safe-action/src/next/errors/router.ts

@@ -0,0 +1,13 @@
+// Comes from https://github.com/vercel/next.js/blob/canary/packages/next/src/client/components/is-next-router-error.ts
+
+import { isHTTPAccessFallbackError, type HTTPAccessFallbackError } from "./http-access-fallback";
+import { isRedirectError, type RedirectError } from "./redirect";
+
+/**
+ * Returns true if the error is a navigation signal error. These errors are
+ * thrown by user code to perform navigation operations and interrupt the React
+ * render.
+ */
+export function isNextRouterError(error: unknown): error is RedirectError | HTTPAccessFallbackError {
+	return isRedirectError(error) || isHTTPAccessFallbackError(error);
+}

packages/next-safe-action/src/utils.ts

@@ -1,14 +1,3 @@
-import type { HTTPAccessFallbackError } from "next/dist/client/components/http-access-fallback/http-access-fallback.js";
-import {
-	getAccessFallbackHTTPStatus,
-	isHTTPAccessFallbackError,
-} from "next/dist/client/components/http-access-fallback/http-access-fallback.js";
-import { isNextRouterError } from "next/dist/client/components/is-next-router-error.js";
-import { isRedirectError } from "next/dist/client/components/redirect-error.js";
-import { isDynamicUsageError } from "next/dist/export/helpers/is-dynamic-usage-error.js";
-import { isPostpone } from "next/dist/server/lib/router-utils/is-postpone.js";
-import { isBailoutToCSRError } from "next/dist/shared/lib/lazy-dynamic/bailout-to-csr.js";
-
 export const DEFAULT_SERVER_ERROR_MESSAGE = "Something went wrong while executing the operation.";
 
 /**
@@ -23,22 +12,3 @@ export const isError = (error: unknown): error is Error => error instanceof Erro
 export const winningBoolean = (...args: (boolean | undefined | null)[]) => {
 	return args.reduce((acc, v) => (typeof v === "boolean" ? v : acc), false) as boolean;
 };
-
-// Next.js error handling
-export function isFrameworkError(error: unknown): error is Error {
-	return isNextRouterError(error) || isBailoutToCSRError(error) || isDynamicUsageError(error) || isPostpone(error);
-}
-
-export function isNotFoundError(error: unknown): error is HTTPAccessFallbackError {
-	return isHTTPAccessFallbackError(error) && getAccessFallbackHTTPStatus(error) === 404;
-}
-
-export function isForbiddenError(error: unknown): error is HTTPAccessFallbackError {
-	return isHTTPAccessFallbackError(error) && getAccessFallbackHTTPStatus(error) === 403;
-}
-
-export function isUnauthorizedError(error: unknown): error is HTTPAccessFallbackError {
-	return isHTTPAccessFallbackError(error) && getAccessFallbackHTTPStatus(error) === 401;
-}
-
-export { isRedirectError };

website/docs/getting-started.mdx

@@ -8,28 +8,14 @@ import TabItem from '@theme/TabItem';
 
 # Getting started
 
-:::info Requirements (>= 7.10.0)
-
-- Next.js 15.1
-- React >= 19
-- TypeScript >= 5
-- A supported validation library: Zod, Valibot, Yup, TypeBox
-:::
-
-:::info Old requirements (\<= 7.9.9)
+:::info Requirements
 
 - Next.js >= 14 (>= 15 for [`useStateAction`](/docs/execute-actions/hooks/usestateaction) hook)
 - React >= 18.2.0
 - TypeScript >= 5
 - A supported validation library: Zod, Valibot, Yup, TypeBox
 :::
 
-
-
-:::warning
-Next.js >= 15.1 and React 19 are required for using next-safe-action >= 7.10.0. This is due to internal error handling framework changes. So, please upgrade to the latest version to use this library with Next.js 15.0.5 or later.
-:::
-
 **next-safe-action** provides a typesafe Server Actions implementation for Next.js App Router applications.
 
 ## Installation