10 min read
React Server Components Explained
Dive deep into React Server Components and understand how they're revolutionizing the way we build React applications with better performance.
ReactServer ComponentsPerformance
# React Server Components Explained
React Server Components (RSC) represent a fundamental shift in how we build React applications. They enable us to render components on the server, reducing bundle size and improving performance.
## What Are Server Components?
Server Components are React components that render on the server and send their output to the client. Unlike traditional SSR, Server Components don't hydrate on the client—they remain server-only.
## Key Benefits
### 1. Reduced Bundle Size
Server Components don't ship JavaScript to the client, significantly reducing bundle size.
### 2. Direct Database Access
Server Components can directly access databases and APIs without exposing credentials to the client.
### 3. Improved Performance
By rendering on the server, we reduce the work the client needs to do.
## Server vs Client Components
### Server Components (Default)
``
jsx
// This runs on the server
export default async function BlogPost({ id }) {
const post = await db.posts.findById(id)
return (
{post.title}
{post.content}
)
}
`
### Client Components
jsx
'use client'
import { useState } from 'react'
// This runs on the client
export default function Counter() {
const [count, setCount] = useState(0)
return (
)
}
`
## Composition Patterns
### Server Component with Client Component Children
jsx
// ServerLayout.jsx (Server Component)
export default function ServerLayout({ children }) {
return (
Server-rendered header
{children}
)
}
// ClientInteractive.jsx (Client Component)
'use client'
export default function ClientInteractive() {
const [state, setState] = useState()
return Interactive content
}
// Page.jsx (Server Component)
export default function Page() {
return (
)
}
`
## Data Fetching Patterns
### Parallel Data Fetching
jsx
async function getData() {
const [posts, users] = await Promise.all([
fetch('/api/posts'),
fetch('/api/users')
])
return {
posts: await posts.json(),
users: await users.json()
}
}
export default async function Dashboard() {
const { posts, users } = await getData()
return (
)
}
`
### Sequential Data Fetching
jsx
export default async function UserProfile({ userId }) {
const user = await getUser(userId)
const posts = await getUserPosts(user.id)
return (
)
}
`
## Streaming and Suspense
Server Components work seamlessly with React Suspense for streaming:
jsx
import { Suspense } from 'react'
export default function Page() {
return (
My App
Loading posts... }>
Loading sidebar... )
}
`
## Best Practices
1. **Use Server Components by default** and only add 'use client' when needed
2. **Keep the client boundary as low as possible** in your component tree
3. **Pass serializable props** between server and client components
4. **Leverage streaming** with Suspense for better UX
## Common Pitfalls
### 1. Importing Server Components in Client Components
jsx
// ❌ This won't work
'use client'
import ServerComponent from './ServerComponent'
export default function ClientComponent() {
return
}
`
### 2. Using Browser APIs in Server Components
jsx
// ❌ This will cause an error
export default function ServerComponent() {
const width = window.innerWidth // window is not available on server
return Width: {width}
}
``## Migration Strategy
1. **Start with new features** using Server Components
2. **Gradually convert existing components** that don't need client-side interactivity
3. **Use the composition pattern** to mix server and client components
4. **Measure performance improvements** as you migrate
## Conclusion
React Server Components are a powerful addition to the React ecosystem. They enable better performance, smaller bundle sizes, and more secure applications by moving computation to the server.
While there's a learning curve, the benefits make Server Components essential for modern React applications. Start experimenting with them in your next project!