Next.js 2.0

More than 3.1 million developers read our announcement post of Next.js. More than 110 contributors have submitted patches, examples or improved our documentation. Over 10,000 developers have starred us on GitHub.

Today, we are proud to introduce Next 2.0 to the world. What follows is a quick summary of every new feature and improvement we have made.

React Made Easy and Simple

Next.js is a very slim yet powerful framework. Place React components in a pages directory and running next, and you'll get automatic code splitting, routing, hot code reloading and universal (server-side and client-side) rendering.

It's easy because it's one command for development (next), and two others (next build and next start) for a production-ready app.

It's simple because it composes really well. It plays well with the rest of the React and JavaScript (npm) ecosystems.
It's also very small. Check out the README: the entire framework's documentation is a 5 minute read.

NEW! Want to learn step-by-step, by example? Check out the Learn Next.js tutorial!

Programmatic API

When we launched Next.js, there was no way to do dynamic routing or load your custom server code. We did this because we believe in shipping early and often.

Now, you can run node index.js to boot up your own custom server and take full control of the routing and rendering pipeline. This enables powerful features like fancy URLs or custom caching schemes.

const express = require('express')
const next = require('next')

const dev = process.env.NODE_ENV !== 'production'
const app = next({ dev })
const handle = app.getRequestHandler()

app.prepare().then(() => {
  const server = express()

  server.get('/r/:subreddit', (req, res) => {
    return app.render(req, res, '/b', {
      ...req.query,
      subreddit: req.params.subreddit
    })
  })

  server.get('*', (req, res) => {
    handle(req, res)
  })
  server.listen(3000)
})

Bring Your Own React

To start a project, you now need to bring in next and two extra deps: react and react-dom.

npm install --save next react react-dom

This has tremendous benefits, at the tiny cost of two extra parameters in the initial `install` to set up your project:

• You can pin React to the version that you know works well on your project

• It makes Next.js codebase clean and pluggable

• You can update React independently of us. e.g: no waiting for a Next.js release after React gets updated

• You can experiment with alternative implementations of the React API. We have examples for Inferno and Preact!

Component CSS Support

Our mission is to make Next.js as familiar as possible to developers on the Web Platform. To that end, next/css is now deprecated in favor of styled-jsx, a Babel transformation that gives us scoped (isolated) full CSS support.

This is what a component with CSS that's local, conflict-free, server-rendered and injected once per instance looks like:

export default () => (
  <div>
    <p>hi there</p>

    <style jsx>{`
      p {
        color: red;
      }
    `}</style>
  </div>
)

You can read more about styled-jsx on its GitHub repository.

Pre-fetching

We implemented the prefetch attribute for the <Link> component.

export default () => (
  <div>
    <Link href="/next-page" prefetch>Go to the next page</Link>
  </div>
)

And just like that, you get the performance of a "SPA", without the initial download and expensive bootup penalty of big bundles. Combined with server rendering, this typically means extraordinary performance with very little effort.

Next News

We think a better "Hello World" app than TodoMVC is actually… Hacker News!

Our implementation, Next News, is fully server-rendered, queries the data over Firebase and updates in realtime as new votes come in. Check out the demo at next-news.vercel.app.

To show off our ability to both partially or fully server render, while having the freedom to execute arbitrary codepaths on the client (upon componentDidMount), notice that we show a "Loading…" message when loading an item on the client, but not when we server-render. This makes us a less strict clone, but it's for a good cause.

We also went as far as replicating the style-less HN login page. Each top-level component (page) in Next.js defines the entirety of the document. There's no notion of global layouts or configuration, only composition via React's component system, which gives you great flexibility.

More Examples

We're very thankful to our community for having submitted so many examples of backends (Express, HAPI, Koa…), styling systems (cxs, glamor, styled-components…), testing systems (jest), type systems (TypeScript and Flow), data fetching (Apollo) and many others.

You can find them all in our GitHub repository.

Scalable HMR (Hot Module Replacement)

Out of the box, Webpack watches and recompiles your entire project upon any change. We found that HMR was therefore not scaling well as our projects grew in number of code-splitting entry points and components.

We deployed a new lazy compilation mechanism that only subscribes to the pages that you're actually working on (i.e.: all the component trees currently rendered).

In our tests, this has made compilation 10 to 20 times faster for large projects.

A Smaller Build

We've made some important improvements to how builds work:

• We set up Webpack common chunks to avoid shipping repeated code across components

• We use hashes to make the initial bundle files be cached permanently on clients, making page loads faster

• We added provisions to make sure an app works correctly

The best part? Every Next.js app is now smaller and more efficient.

We are working on making Next.js much smaller and we have identified many opportunities for optimization already.

The React team is also working on size optimizations for React Fiber, which we will begin testing soon.

Fully Extensible

Many of the examples above introduce new features to the code or the build process. This is possible because Next.js gives you complete control over Babel's and Webpack's configuration.

To extend Babel, we let you apply Next.js' settings as a preset.

{
  "name': "my-next-app",
  […]
  "babel": {
    "presets": ["next/babel"],
    "plugins": [[
      "transform-define",
      "./env-config.js"
    ]]
  }
}

To extend webpack or tweak other settings, you can define a next.config.js file. Check out the README for the complete documentation.

Featured at ReactConf

Our CEO Guillermo Rauch presented Next.js at ReactConf in Santa Clara a few weeks ago. Check it out!

The Road to 3.0

We attribute our success with this release to having released early, iterated frequently and listened to our community. But something extremely important as well was making our roadmap and priorities clear and public.

Here are some of the goals for the coming releases on our way to 3.0:

Improved HMR

We are still working on a few improvements to hot module replacement. Some errors don't have accurate locations and there are a few issues with recovering from errors in certain scenarios.

Faster Dev Compilation

We are investigating ways to continue to optimize the development experience. Since both Node.js and modern browsers that developers use iterate so quickly, we can skip large portions of the compilation step for really fast reloads.

Seamless Support for Lazy import()

This will allow for server-rendered pages that expose different JS components according to the data they used, for example. In addition, once the component mounts on the client, you can load any component you want, lazily.

Note: this already partially works, but we will continue to refine it an document it.

React Fiber

We are looking forward to testing and ensuring Next.js works perfectly with the upcoming React engine: Fiber. This will potentially introduce new opportunities, like the ability to stream HTML from the server as it is generated.

Static Exports

You should be able to server-render to files via a next export command. In other words, you'll be able to statically export your application to HTML files.

Ready for Production

Aside from this very website, we are very happy many others in the industry have adopted Next.js. Here are some that have let us know.

• NPM

• Scale

• Open Collective

• Tutor Bro

• Upsum News

• Skys Limo

• Project R

If you have shipped Next.js to production or are planning to, please let us know. We are always hanging out on the #next channel in our Public Slack community.

We are bringing together the Next.js community at our one-day conference ZEIT Day on April 29th in San Francisco. It's a unique opportunity to meet other users and learn more about it from its creators!