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ESLint is Now Language-Agnostic: Linting JSON, Markdown, and Beyond
ESLint has added JSON and Markdown linting support with new officially-supported plugins, expanding its versatility beyond JavaScript.
The 'next' npm package is a popular framework for building server-side rendered and statically generated React applications. It provides a set of features that simplify the development of modern web applications, including page-based routing, pre-rendering, automatic code splitting, and API routes.
Page-based routing
Next.js provides a file-system-based router built on the concept of pages. When a file is added to the pages directory, it's automatically available as a route.
export default function Home() {
return <div>Welcome to Next.js!</div>
}
API Routes
Next.js allows you to create API endpoints as part of your Next.js application. These are server-side functions that you can deploy alongside your application.
export default function handler(req, res) {
res.status(200).json({ message: 'Hello from Next.js!' })
}
Static Generation and Server-Side Rendering
Next.js supports two forms of pre-rendering: Static Generation and Server-Side Rendering. This feature allows you to generate HTML in advance for optimal performance.
export async function getStaticProps() {
const data = await fetchData();
return { props: { data } };
}
Built-in CSS and Sass Support
Next.js allows you to import CSS and Sass files directly within your JavaScript components, providing a streamlined development experience.
import '../styles/globals.css';
export default function App({ Component, pageProps }) {
return <Component {...pageProps} />
}
Automatic Code Splitting
Next.js automatically splits your code into small bundles that are loaded as needed, improving load times and performance.
import dynamic from 'next/dynamic';
const DynamicComponent = dynamic(() => import('../components/hello'));
export default function Home() {
return <DynamicComponent />
}
Gatsby is a React-based static site generator that provides similar functionalities to Next.js, such as pre-rendering and code splitting. However, Gatsby is more focused on static site generation, whereas Next.js offers a hybrid approach with both static generation and server-side rendering.
Nuxt.js is a framework based on Vue.js that offers functionalities similar to Next.js but for Vue.js applications. It provides server-side rendering, static site generation, and automatic code splitting, much like Next.js does for React applications.
Create React App is a boilerplate to create single-page React applications. It sets up a development environment and builds scripts but does not offer server-side rendering or static site generation out of the box like Next.js does.
Sapper is a framework for building web applications using Svelte, offering server-side rendering and static site generation. It's similar to Next.js in terms of goals but is designed for Svelte instead of React.
Next.js is a minimalistic framework for server-rendered React applications.
Install it:
$ npm install next --save
and add a script to your package.json like this:
{
"scripts": {
"dev": "next"
}
}
After that, 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 npm run dev
and go to http://localhost:3000
So far, we get:
./pages
./static/
is mapped to /static/
To see how simple this is, check out the sample app - nextgram
Every import
you declare gets bundled and served with each page
import React from 'react'
import cowsay from 'cowsay-browser'
export default () => (
<pre>{ cowsay.say({ text: 'hi there!' }) }</pre>
)
That means pages never load unnecessary code!
We use glamor to provide a great built-in solution for CSS isolation and modularization without trading off any CSS features.
Glamor's HowTo shows converting various CSS use cases to Glamor. See Glamor's API docs for more details.
import React from 'react'
import css, {insertRule} from 'next/css'
export default () => (
<div className={style}>
Hello world
</div>
)
// Global CSS rule
insertRule("html, body { margin: 0; padding: 0; }")
const style = css({
background: 'red',
':hover': {
background: 'gray'
},
'@media (max-width: 600px)': {
background: 'blue'
}
})
<head>
side effectsWe 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 () => (
<div>
<Head>
<title>My page title</title>
<meta name="viewport" content="initial-scale=1.0, width=device-width" />
</Head>
<p>Hello world!</p>
</div>
)
When you need state, lifecycle hooks or initial data population you can export a React.Component
.
import React from 'react'
export default class extends React.Component {
static async getInitialProps ({ req }) {
return req
? { userAgent: req.headers['user-agent'] }
: { userAgent: navigator.userAgent }
}
render () {
return <div>
Hello World {this.props.userAgent}
</div>
}
}
Notice that to load data when the page loads, we use getInitialProps
which is an async
static method. It can asynchronously fetch anything that resolves to a JavaScript plain Object
, which populates props
.
For the initial page load, getInitialProps
will execute on the server only. getInitialProps
will only be executed on the client when navigating to a different route via the Link
component and the props.url
.
getInitialProps
receives a context object with the following properties:
pathname
- path section of URLquery
- query string section of URL parsed as an objectreq
- HTTP request object (server only)res
- HTTP response object (server only)xhr
- XMLHttpRequest object (client only)err
- Error object if any error is encountered during the renderingClient-side transitions between routes are enabled via a <Link>
component
import React from 'react'
import Link from 'next/link'
export default () => (
<div>Click <Link href="/about"><a>here</a></Link> to read more</div>
)
import React from 'react'
export default () => (
<p>Welcome to About!</p>
)
Client-side routing behaves exactly like the native UA:
getInitialProps
, data is fetched. If an error occurs, _error.js
is renderedpushState
is performed and the new component renderedEach top-level component receives a url
property with the following API:
pathname
- String
of the current path excluding the query stringquery
- Object
with the parsed query string. Defaults to {}
push(url)
- performs a pushState
call associated with the current componentreplace(url)
- performs a replaceState
call associated with the current componentpushTo(url)
- performs a pushState
call that renders the new url
. This is equivalent to following a <Link>
replaceTo(url)
- performs a replaceState
call that renders the new url
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 class Error extends React.Component {
static getInitialProps ({ res, xhr }) {
const statusCode = res ? res.statusCode : xhr.status
return { statusCode }
}
render () {
return (
<p>An error { this.props.statusCode } occurred</p>
)
}
}
To deploy, instead of running next
, you probably want to build ahead of time. Therefore, building and starting are separate commands:
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"
}
}
Then run now
and enjoy!
Note: we recommend putting .next
in .npmignore
or .gitignore
. Otherwise, use files
or now.files
to opt-into a whitelist of files you want to deploy (and obviously exclude .next
)
We’re ecstatic about both the developer experience and end-user performance, so we decided to share it with the community.
The client side next bundle, which includes React and Glamor is 73kb gzipped.
The Next runtime (lazy loading, routing, <Head>
) contributes around 15% to the size of that bundle.
The codebase is ~1500LOC (excluding CLI programs).
Yes and No.
Yes in that both make your life easier.
No in that it enforces a structure so that we can do more advanced things like:
In addition, Next.js provides two built-in features that are critical for every single website:
<Link>
(by importing next/link
)<head>
: <Head>
(by importing next/head
)If you want to create re-usable React components that you can embed in your Next.js app or other React applications, using create-react-app
is a great idea. You can later import
it and keep your codebase clean!
next/css
is powered by Glamor. While it exposes a JavaScript API, it produces regular CSS and therefore important features like :hover
, animations, media queries all work.
There’s no tradeoff in power. Instead, we gain the power of simpler composition and usage of JavaScript expressions.
Compiling regular CSS files would be counter-productive to some of our goals. Some of these are listed below.
Please note: we are very interested in supporting regular CSS, since it's so much easier to write and already familiar. To that end, we're currently exploring the possibility of leveraging Shadow DOM to avoid the entire CSS parsing and mangling step [#22]
Parsing, prefixing, modularizing and hot-code-reloading CSS can be avoided by just using JavaScript.
This results in better compilation performance and less memory usage (especially for large projects). No cssom
, postcss
, cssnext
or transformation plugins.
It also means fewer dependencies and fewer things for Next to do. Everything is Just JavaScript® (since JSX is completely optional)
Since every class name is invoked with the css()
helper, Next.js can intelligently add or remove <style>
elements that are not being used.
This is important for server-side rendering, but also during the lifecycle of the page. Since Next.js enables pushState
transitions that load components dynamically, unnecessary <style>
elements would bring down performance over time.
This is a very significant benefit over approaches like require(‘xxxxx.css')
.
Since the class names and styles are defined as JavaScript objects, a variety of aids for correctness are much more easily enabled:
While these are tractable for CSS itself, we don’t need to duplicate the efforts in tooling and libraries to accomplish them.
We track V8. Since V8 has wide support for ES6 and async
and await
, we transpile those. Since V8 doesn’t support class decorators, we don’t transpile those.
Next.js is special in that:
getInitialProps
that should block the loading of the route (either when server-rendering or lazy-loading)As a result, we were able to introduce a very simple approach to routing that consists of two pieces:
url
object to inspect the url or perform modifications to the history<Link />
component is used to wrap elements like anchors (<a/>
) to perform client-side transitionsWe tested the flexibility of the routing with some interesting scenarios. For an example, check out nextgram.
We’re adding the ability to map between an arbitrary URL and any component by supplying a request handler: #25
On the client side, we'll add a parameter to <Link>
so that it decorates the URL differently from the URL it fetches.
It’s up to you. getInitialProps
is an async
function (or a regular function that returns a Promise
). It can retrieve data from anywhere.
Yes! Here's an example
We intend for Next.js to be a great starting point for any website or app, no matter how small.
If you’re building a very small mostly-content website, you still want to benefit from features like lazy-loading, a component architecture and module bundling.
But in some cases, the size of React itself would far exceed the content of the page!
For this reason we want to promote a situation where users can share the cache for the basic runtime across internet properties. The application code continues to load from your server as usual.
We are committed to providing a great uptime and levels of security for our CDN. Even so, we also automatically fall back if the CDN script fails to load with a simple trick.
To turn the CDN off, just set { “next”: { “cdn”: false } }
in package.json
.
Many of the goals we set out to accomplish were the ones listed in The 7 principles of Rich Web Applications by Guillermo Rauch.
The ease-of-use of PHP is a great inspiration. We feel Next.js is a suitable replacement for many scenarios where you otherwise would use PHP to output HTML.
Unlike PHP, we benefit from the ES6 module system and every file exports a component or function that can be easily imported for lazy evaluation or testing.
As we were researching options for server-rendering React that didn’t involve a large number of steps, we came across react-page (now deprecated), a similar approach to Next.js by the creator of React Jordan Walke.
The following issues are currently being explored and input from the community is appreciated:
FAQs
The React Framework
The npm package next receives a total of 6,034,270 weekly downloads. As such, next popularity was classified as popular.
We found that next demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 3 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
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