refactor: remove clone method

`clone` was used to extend an action client with new middleware functions. Now you can directly use
`use` method to extend your action client(s), since it will return a new instance of the action
client itself, with previous cloned middleware functions + the one you just passed to `use`.

packages/example-app/src/lib/safe-action.ts

@@ -62,8 +62,6 @@ async function getSessionId() {
 }
 
 export const authAction = action
-	// Clone the base client to extend this one with additional middleware functions.
-	.clone()
 	// In this case, context is used for (fake) auth purposes.
 	.use(async ({ next }) => {
 		const userId = randomUUID();

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

@@ -49,19 +49,6 @@ class SafeActionClient<const ServerError, const Ctx = null, const Metadata = nul
 		this.#handleReturnedServerError = opts.handleReturnedServerError;
 	}
 
-	/**
-	 * Clone the safe action client keeping the same middleware and initialization functions.
-	 * This is used to extend the base client with additional middleware functions.
-	 * @returns {SafeActionClient}
-	 */
-	public clone() {
-		return new SafeActionClient<ServerError, Ctx, Metadata>({
-			handleReturnedServerError: this.#handleReturnedServerError,
-			handleServerErrorLog: this.#handleServerErrorLog,
-			middlewareFns: [...this.#middlewareFns], // copy the middleware stack so we don't mutate it
-		});
-	}
-
 	/**
 	 * Use a middleware function.
 	 * @param middlewareFn Middleware function
@@ -71,7 +58,7 @@ class SafeActionClient<const ServerError, const Ctx = null, const Metadata = nul
 		this.#middlewareFns.push(middlewareFn);
 
 		return new SafeActionClient<ServerError, NextCtx, Metadata>({
-			middlewareFns: this.#middlewareFns,
+			middlewareFns: [...this.#middlewareFns, middlewareFn],
 			handleReturnedServerError: this.#handleReturnedServerError,
 			handleServerErrorLog: this.#handleServerErrorLog,
 		});

website/docs/recipes/extending-base-client.md

@@ -27,8 +27,6 @@ export const actionClient = createSafeActionClient().use(async ({ next }) => {
 // action server code function. Note that by extending the base client, you don't need to
 // redeclare the logging middleware, is will simply be inherited by the new client.
 export const authActionClient = actionClient
-  // Clone the base client to extend this one with additional middleware functions.
-  .clone()
   // In this case, context is used for (fake) auth purposes.
   .use(async ({ next }) => {
     const session = cookies().get("session")?.value;

website/docs/safe-action-client/instance-methods.md

@@ -7,14 +7,6 @@ description: List of methods of the safe action client.
 
 `createSafeActionClient` creates an instance of the safe action client, which has the following methods:
 
-## `clone`
-
-```typescript
-actionClient.clone() => new SafeActionClient()
-```
-
-`clone` returns a new instance of the safe action client with the same initialization options and middleware functions as the original one. It is used to extend a base client with additional middleware functions. If you don't use `clone` when creating a new client, the middleware function list of the original one will be mutated and extended with the new ones, which is not desirable.
-
 ## `use`
 
 ```typescript

website/docs/usage/middleware.md

@@ -60,8 +60,6 @@ const actionClient = createSafeActionClient({
 // Note that the same initialization options and middleware functions of the base client
 // will also be used for this one.
 const authActionClient = actionClient
-  // Clone the base client so it doesn't get mutated.
-  .clone()
   // Define authorization middleware.
   .use(async ({ next }) => {
     const session = cookies().get("session")?.value;