introduction.md

description
Next.js has a built-in, opinionated, and file-system based Router. You can learn how it works here.

Routing

Next.js has 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.

The files inside the pages directory can be used to define most common patterns.

Index routes

The router will automatically route files named index to the root of the directory.

• pages/index.js → /
• pages/blog/index.js → /blog

Nested routes

The router supports nested files. If you create a nested folder structure, files will automatically be routed in the same way still.

• pages/blog/first-post.js → /blog/first-post
• pages/dashboard/settings/username.js → /dashboard/settings/username

Dynamic route segments

To match a dynamic segment, you can use the bracket syntax. This allows you to match named parameters.

• pages/blog/[slug].js → /blog/:slug (/blog/hello-world)
• pages/[username]/settings.js → /:username/settings (/foo/settings)
• pages/post/[...all].js → /post/* (/post/2020/id/title)

Check out the Dynamic Routes documentation to learn more about how they work.

Linking between pages

The Next.js router allows you to do client-side route transitions between pages, similar to a single-page application.

A React component called Link is provided to do this client-side route transition.

import Link from 'next/link'

function Home() {
  return (
    <ul>
      <li>
        <Link href="/">Home</Link>
      </li>
      <li>
        <Link href="/about">About Us</Link>
      </li>
      <li>
        <Link href="/blog/hello-world">Blog Post</Link>
      </li>
    </ul>
  )
}

export default Home

The example above uses multiple links. Each one maps a path (href) to a known page:

• / → pages/index.js
• /about → pages/about.js
• /blog/hello-world → pages/blog/[slug].js

Any <Link /> in the viewport (initially or through scroll) will be prefetched by default (including the corresponding data) for pages using Static Generation. The corresponding data for server-rendered routes is fetched only when the <Link /> is clicked.

Linking to dynamic paths

You can also use interpolation to create the path, which comes in handy for dynamic route segments. For example, to show a list of posts which have been passed to the component as a prop:

import Link from 'next/link'

function Posts({ posts }) {
  return (
    <ul>
      {posts.map((post) => (
        <li key={post.id}>
          <Link href={`/blog/${encodeURIComponent(post.slug)}`}>
            {post.title}
          </Link>
        </li>
      ))}
    </ul>
  )
}

export default Posts

encodeURIComponent is used in the example to keep the path utf-8 compatible.

Alternatively, using a URL Object:

import Link from 'next/link'

function Posts({ posts }) {
  return (
    <ul>
      {posts.map((post) => (
        <li key={post.id}>
          <Link
            href={{
              pathname: '/blog/[slug]',
              query: { slug: post.slug },
            }}
          >
            {post.title}
          </Link>
        </li>
      ))}
    </ul>
  )
}

export default Posts

Now, instead of using interpolation to create the path, we use a URL object in href where:

• pathname is the name of the page in the pages directory. /blog/[slug] in this case.
• query is an object with the dynamic segment. slug in this case.

Injecting the router

Examples

• Dynamic Routing

To access the router object in a React component you can use useRouter or withRouter.

In general we recommend using useRouter.

Learn more

The router is divided in multiple parts:

next/link: Handle client-side navigations.

next/router: Leverage the router API in your pages.