3.9 KiB
next.js
Next.js
is a minimalistic framework for server-rendered React applications.
How to use
The file-system is the main API. Every .js
file becomes a route that gets automatically processed and rendered.
Populate ./pages/index.js
inside your project:
import React from 'react'
export default () => (
<div>Welcome to next.js!</div>
)
and then just run next
and go to http://localhost:3000
So far, we get:
- Automatic transpilation and bundling (with webpack and babel)
- Hot code reloading
- Server rendering and indexing of
./pages
- Static file serving.
./static/
is mapped to/static/
Bundling (code splitting)
Every import
you declare gets bundled and served with each page
import React from 'react'
import cowsay from 'cowsay'
export default () => (
<pre>{ cowsay('hi there!') }</pre>
)
That means pages never load unneccessary code!
CSS
We use Aphrodite to provide a great built-in solution for CSS modularization
import React from 'react'
import { css, StyleSheet } from 'next/css'
export default () => {
<div className={ css(styles.main) }>
Hello world
</div>
})
const styles = StyleSheet.create({
main: {
background: 'red',
'@media (max-width: 600px)': {
background: 'blue'
}
}
})
<head>
side effects
We expose a built-in component for appending elements to the <head>
of the page.
import React from 'react'
import Head from 'next/head'
export default () => (
<Head>
<title>My page title</title>
<meta name="viewport" content="initial-scale=1.0, width=device-width" />
</Head>
<p>Hello world!</p>
)
Stateful components
When state, lifecycle hooks or initial data population you can export a React.Component
:
import React from 'react'
export default class extends React.Component {
async getInitialProps ({ isServer, req }) {
return isServer
? { userAgent: req.headers.userAgent }
: { userAgent: navigator.userAgent }
}
render () {
return <div>
Hello World {this.props.userAgent}
</div>
}
}
Routing
Client-side transitions between routes are enabled via a <Link>
component
pages/index.js
import React from 'react'
import Link from 'next/link'
export default () => (
<div>Click <Link href="/about"><a>here</a></Link> to read more</div>
)
pages/about.js
import React from 'react'
export default () => (
<p>Welcome to About!</p>
)
Client-side routing behaves exactly like the native UA:
- The component is fetched
- If it defines
getInitialProps
, data is fetched. If an error occurs,_error.js
is rendered - After 1 and 2 complete,
pushState
is performed and the new component rendered
Each top-level component receives a url
property with the following API:
path
-String
of the current path excluding the query stringquery
-Object
with the parsed query string. Defaults to{}
push(url)
- performs apushState
call associated with the current componentreplace(url)
- performs areplaceState
call associated with the current componentpushTo(url)
- performs apushState
call that renders the newurl
. This is equivalent to following a<Link>
replaceTo(url)
- performs areplaceState
call that renders the newurl
Error handling
404 or 500 errors are handled both client and server side by a default component error.js
. If you wish to override it, define a _error.js
:
import React from 'react'
export default ({ statusCode }) => (
<p>An error { statusCode } occurred</p>
)
Production deployment
To deploy, run:
next build
next start
For example, to deploy with now
a package.json
like follows is recommended:
{
"name": "my-app",
"dependencies": {
"next": "latest"
},
"scripts": {
"dev": "next",
"build": "next build",
"start": "next start"
}
}