Intro

If you're a web developer using React, you may have heard about server components and how they can take your skills to the next level. But what are react server components exactly, and how do you use them? In this beginner's guide, we'll dive into the world of server components and explore their features and capabilities.

We'll also compare them to regular react components and explain how the use client directive play a crucial role in their functionality. So let's get started and discover the exciting world of react server components!

Understanding What Server Components Are

React 18 introduces a fresh feature known as Server Components, enabling developers to construct UI components that operate solely on the server, a departure from conventional React components which render on the client-side. Server Components harness the power of server-side technologies, improving initial render speeds, enhancing performance, and reducing the amount of JavaScript sent to the client.

A prime benefit of Server Components is their capacity to fetch and manage data on the server, diminishing the necessity for extra network requests on the client-side.

Take, for example, a React Server Component's capability to smoothly merge with established node.js libraries, such as mysql2 or Node.js fs module.

import fs from "fs/promises";

export async function ViewFile() {
  const file = await fs.readFile("file.txt", "utf-8");
  return <div>{file}</div>;
}

The resultant impact on application performance is significantly positive and simplifies the overall implementation process. Server components do, however, need a supporting framework like Next.js. The creation process mirrors that of standard React components, with a minor drawback that interactive elements such as click handlers and effects don't function within them. However, this limitation isn't detrimental as Server Components can render standard React components, which can include these interactive features.

Exploring the Unique Features of Server Components

Server components introduce numerous special functionalities and attributes, enhancing the web development journey significantly. Let's delve deeper into these aspects and understand their advantages in React applications.

Server-side APIs:

A remarkable feature of server components is their compatibility with server-side APIs. By using server components, you can now transition from solely relying on client-side rendering, a trait of conventional React components, to server-side rendering of UI components. Consequently, this reduces the initial render times for your users, facilitating a more immediate and reactive user interface. Server components also exhibit capabilities in data fetching and implementing server-side logic, further strengthening their usefulness.

Code splitting:

An intrinsic feature of server components is the automated code splitting for client code. Only the necessary code required to run the application is transmitted to the client, optimizing the user experience based on their interaction level with the app. For instance, if your app features logged in and logged out versions, only the required version's code will be fetched by the respective users.

Streaming:

React Server Components (RSCs) allows the UI to stream as soon as it's ready. Coupled with Suspense, RSCs promptly render an app shell comprising the app's overall layout while dynamically streaming the remaining components as they're prepared.

import { Suspense } from "react";

export default function Stream() {
  const fallback = (
    <div className="flex animate-pulse p-6 w-full h-6 bg-stone-300 rounded items-end justify-center text-center">
      <div>Loading..</div>
    </div>
  );

  return (
    <div className="px-5">
      <h1 className="text-xl">Stream</h1>
      <p>
        This page is used to test the streaming functionality of the site. It
        will stream in UI as it is ready
      </p>
      <div className="flex flex-col space-y-4 max-w-lg">
        <Suspense fallback={fallback}>
          <UI delay={1000}>1</UI>
        </Suspense>
        <Suspense fallback={fallback}>
          <UI delay={2000}>2</UI>
        </Suspense>
        <Suspense fallback={fallback}>
          <UI delay={3000}>3</UI>
        </Suspense>
      </div>
    </div>
  );
}

async function UI({
  children,
  delay,
}: {
  children: React.ReactNode;
  delay: number;
}) {
  await sleep(delay);
  return (
    <div className="p-6 w-full h-6 bg-stone-300 rounded flex text-center justify-center items-center">
      <div>{children}</div>
    </div>
  );
}

const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));

To encapsulate, server components offer a variety of special features and capabilities to React development, thus significantly improving the experience.

How to Use Server Components

Having a solid grasp on server components and their distinct traits, let's delve into their application in your React projects. In this portion, we'll walk through the preliminary steps with server components, alongside some recommended practices for their efficient usage. Firstly, a server-side runtime like Next.js is essential.

In Next.js, all components are server components by default. Thus, their usage simply requires creating a new component and rendering it via the Next.js App Router.

The directive "use client" can be applied at a module's outset, thereby designating the module as a client-side component or tree's entry point. For instance, if an RSC renders the app layout, but there is a need for an interactive button, segregate this button into a new module, append the "use client" at the beginning, and consolidate all interaction logic within that module or modules it imports. The "use client" categorizes the module and its dependencies as client-side ones.

The Use of Client Directive

In the exciting world of React server components, understanding the use of the client directive is crucial. This directive play a vital role in providing interactivity for your server components. So, let's dive into the specifics and how it contribute to the development process. The "use client" directive is a powerful tool that allows you to define the what components should not be server components. This includes handling user interactions and rendering updates on the client. With the "use client" directive, you can seamlessly integrate the client-side functionality with the server components, creating a cohesive and interactive user experience.

"use client";
// MyButton.tsx
import { useState } from "react";
import { Modal } from "@my-ui-lib";

export function MyButton() {
  const [open, setOpen] = useState(false);
  return (
    <>
      <Modal open={open} onClose={() => setOpen(false)}>
        <h1>This is my modal</h1>
      </Modal>
      <button onClick={() => setOpen(true)}>Open modal</button>
    </>
  );
}

// page.tsx
import { MyButton } from "./MyButton";

export default function MyServerComponent() {
  return (
    <div>
      <MyButton />
    </div>
  );
}

By utilizing the Next.js app router, you can navigate between different server components and build dynamic and interactive UI flows. This powerful routing capability allows you to create complex applications with ease. When using the client directive, it's essential to separate the client and server components effectively. By doing so, you can ensure that each component has clear responsibilities, leading to better code organization and modularity. This separation of concerns simplifies the development process and makes it easier to maintain and debug your server components.

Check out the React docs for use client directive for more information on how to use the client directive.

Comparing Server Components and Regular React Components

Now that we have a good understanding of what server components are and how to use them, let's take a moment to compare them to regular React components. Server components bring a range of unique features and capabilities to the table that set them apart from their traditional counterparts. One key difference between server components and regular React components is the ability to leverage server-side APIs. Regular React components rely solely on client-side APIs. In contrast, server components can only use server APIs.

In terms of implementation, server components work seamlessly with server-side runtimes like Next.js and Node.js. Regular React components, on the other hand, do not have this level of integration with server-side runtimes. In summary, server components offer unique advantages over regular React components in terms of rendering flexibility and data handling. With their ability to leverage server-side rendering and handle server-side logic, server components can significantly enhance the performance and responsiveness of your applications. Whether you choose to use Next.js, or another server-side runtime, server components are a powerful tool that can take your React development to the next level.

FAQs

Q: How do I know if a component is a server component?

A component that is async is a server component. If it contains the use client directive, or if it contains event handlers or useEffects it is a client component. If it contains neither, it is a shared component that can be used in both server and client components.

Server component

export async function MyServerComponent() {
  return <div>hello world</div>;
}

Shared component

export function MyClientComponent() {
  return <div>hello world</div>;
}

Client component with event handlers

export function MyClientComponent() {
  const [count, setCount] = useState(0);
  return (
    <div>
      <div>hello world</div>
      <button onClick={() => setCount(count + 1)}>Click me</button>
    </div>
  );
}

Client component with useEffect

export function MyClientComponent() {
  useEffect(() => {
    console.log("hello world");
  }, []);
  return <div>hello world</div>;
}

Client component with use client directive

"use client";
export function MyClientComponent() {
  return <div>hello world</div>;
}

Q: Can I use server components with Next.js?

Yes, you can use server components with Next.js. Next.js is a server-side runtime for React that allows you to build fast and efficient web applications. It provides a powerful routing system that makes it easy to create dynamic and interactive UI flows. With Next.js, you can leverage server components to enhance the performance and responsiveness of your applications.

Check out the Next.js App Router documentation for more information on how to use server components with Next.js.

Q: What are the benefits of using server components?

• Streaming
• Code splitting
• Server-side APIs
• Suspense for data fetching
• Less JavaScript sent to the client

Q: What are the drawbacks of using server components?

Requires a framework like Next.js to work. You can't use server components with vanilla React.

Conclusion - The Impact of Server Components

In summary, server components have a significant impact on React development. Whether you choose Next.js or another server-side runtime, server components can enhance the performance, responsiveness, and efficiency of your web applications. They open up a world of possibilities for building fast and efficient user interfaces. So don't hesitate to explore the exciting realm of React server components and take your development skills to new heights!