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A Quick Introduction to Action Client Components in NextJS 14

Call your actions through this component and get in return client components with data fetched from the server!

In NextJS 14 you can make an Action client component like this:

"use client";

import { Suspense, useState, useEffect } from "react";

export default function Action({
  fallback = <>loading...</>,
}) {
  const [JSX, setJSX] = useState(fallback);

  useEffect(() => {
    setJSX(<Suspense fallback={fallback}>{action(props)}</Suspense>);
  }, [softKey]);

  return JSX;

Then you can use it like this in any client component (also server component):

"use client";

import Action from "@/app/action";
import { greeting } from "@/app/actions/greeting";
import { useEffect, useState } from "react";

export default function Client1() {
  const [userId, setUserId] = useState(1);
  const [softKey, setSoftKey] = useState(0);

  useEffect(() => {
    setSoftKey((k) => k + 1);
  }, [userId]);

  return (
      <Action action={greeting} userId={userId} softKey={softKey} />
        onClick={() => {

In this case greeting action is like this:

"use server";

import Greeting from "@/app/action-components/greeting";
import MyError from "@/app/action-components/my-error";

const DELAY = 500;

const users = [
  { id: 1, username: "roggc" },
  { id: 2, username: "roger" },

export async function greeting({ userId }) {
  try {
    const username = await new Promise((r) => {
      setTimeout(() => {
        const user = users.find((u) => === userId);
        if (user) {
      }, DELAY);

    // throw new Error("crash!");
    return <Greeting username={username} />;
  } catch (error) {
    return <MyError errorMessage={error.message} />;

and Greeting client component is like this:

"use client";

export default function Greeting({ username }) {
  return <>hello {username}</>;

You call your Client1 component from Home server component:

import Client1 from "@/app/components/client-1";

export default function Home() {
  return <Client1 />;

But for this to work you must also import greeting action in Home server component or in RootLayout server component, like this:

import { Inter } from "next/font/google";
import { greeting } from "@/app/actions/greeting"; // <-- this is necessary, if not fails to compile

const inter = Inter({ subsets: ["latin"] });

export const metadata = {
  title: "Create Next App",
  description: "Generated by create next app",

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body className={inter.className}>{children}</body>

If you don''t do this last step you get following server error:

⨯ Error: Could not find the module "C:\Users\roggc\dev\nextjs\test1\app\action-components\greeting.js#" in the React Client Manifest. This is probably a bug in the React Server Components bundler. at stringify (<anonymous>)

The idea is any action returns a client component, and are called through Action client component. Action client component accepts an action prop plus any number of other props which will passed to the action itself (except functions, which cannot be stringified; for this last case you must use a library like react-context-slices to store the functions in the global shared state before calling the Action component and recovering its value in the Greeting client component).

This way of coding comes from this setup, also explained here.

Now, with this shown here, you can also code like this in NextJS 14.

The code shown in here is from this repository.

There is also a MyError client component we return in case of error in the server action:

"use client";

export default function MyError({ errorMessage }) {
  return <>Something went wrong: {errorMessage}</>;

So this is the result on the browser when executing. First we see the initial loading...:

initially we se the loading... message on the screen

Then, after the delay in the server, we see the rendered client component with data fetched from the server:

after the delay on the server we see the rendered client component with data fetched from the server

If we click in the button once the process repeats (first the loading... and then the rendered client component with new data fetched from the server).

And when an error occurs in the server we see rendered the MyError client component with the proper error message:

When an error occurs in the server, the MyError client component is returned with the error message

Thanks for reading, I hope you find the content of this post interesting. Happy coding.

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