| --- |
| title: How to upgrade to version 9 |
| nav_title: Version 9 |
| description: Upgrade your Next.js Application from Version 8 to Version 9. |
| --- |
|
|
| To upgrade to version 9, run the following command: |
|
|
| ```bash filename="Terminal" |
| npm i next@9 |
| ``` |
|
|
| ```bash filename="Terminal" |
| yarn add next@9 |
| ``` |
|
|
| ```bash filename="Terminal" |
| pnpm up next@9 |
| ``` |
|
|
| ```bash filename="Terminal" |
| bun add next@9 |
| ``` |
|
|
| > **Good to know:** If you are using TypeScript, ensure you also upgrade `@types/react` and `@types/react-dom` to their corresponding versions. |
|
|
| ## Check your Custom App File (`pages/_app.js`) |
|
|
| If you previously copied the [Custom `<App>`](/docs/pages/building-your-application/routing/custom-app) example, you may be able to remove your `getInitialProps`. |
|
|
| Removing `getInitialProps` from `pages/_app.js` (when possible) is important to leverage new Next.js features! |
|
|
| The following `getInitialProps` does nothing and may be removed: |
|
|
| ```js |
| class MyApp extends App { |
| // Remove me, I do nothing! |
| static async getInitialProps({ Component, ctx }) { |
| let pageProps = {} |
|
|
| if (Component.getInitialProps) { |
| pageProps = await Component.getInitialProps(ctx) |
| } |
|
|
| return { pageProps } |
| } |
|
|
| render() { |
| // ... etc |
| } |
| } |
| ``` |
|
|
| ## Breaking Changes |
|
|
| ### `@zeit/next-typescript` is no longer necessary |
|
|
| Next.js will now ignore usage `@zeit/next-typescript` and warn you to remove it. Please remove this plugin from your `next.config.js`. |
|
|
| Remove references to `@zeit/next-typescript/babel` from your custom `.babelrc` (if present). |
|
|
| The usage of [`fork-ts-checker-webpack-plugin`](https://github.com/Realytics/fork-ts-checker-webpack-plugin/issues) should also be removed from your `next.config.js`. |
|
|
| TypeScript Definitions are published with the `next` package, so you need to uninstall `@types/next` as they would conflict. |
|
|
| The following types are different: |
|
|
| > This list was created by the community to help you upgrade, if you find other differences please send a pull-request to this list to help other users. |
|
|
| From: |
|
|
| ```tsx |
| import { NextContext } from 'next' |
| import { NextAppContext, DefaultAppIProps } from 'next/app' |
| import { NextDocumentContext, DefaultDocumentIProps } from 'next/document' |
| ``` |
|
|
| to |
|
|
| ```tsx |
| import { NextPageContext } from 'next' |
| import { AppContext, AppInitialProps } from 'next/app' |
| import { DocumentContext, DocumentInitialProps } from 'next/document' |
| ``` |
|
|
| ### The `config` key is now an export on a page |
|
|
| You may no longer export a custom variable named `config` from a page (i.e. `export { config }` / `export const config ...`). |
| This exported variable is now used to specify page-level Next.js configuration like Opt-in AMP and API Route features. |
|
|
| You must rename a non-Next.js-purposed `config` export to something different. |
|
|
| ### `next/dynamic` no longer renders "loading..." by default while loading |
|
|
| Dynamic components will not render anything by default while loading. You can still customize this behavior by setting the `loading` property: |
|
|
| ```jsx |
| import dynamic from 'next/dynamic' |
|
|
| const DynamicComponentWithCustomLoading = dynamic( |
| () => import('../components/hello2'), |
| { |
| loading: () => <p>Loading</p>, |
| } |
| ) |
| ``` |
|
|
| ### `withAmp` has been removed in favor of an exported configuration object |
|
|
| Next.js now has the concept of page-level configuration, so the `withAmp` higher-order component has been removed for consistency. |
|
|
| This change can be **automatically migrated by running the following commands in the root of your Next.js project:** |
|
|
| ```bash filename="Terminal" |
| curl -L https://github.com/vercel/next-codemod/archive/master.tar.gz | tar -xz --strip=2 next-codemod-master/transforms/withamp-to-config.js npx jscodeshift -t ./withamp-to-config.js pages*.js |
| ``` |
|
|
| To perform this migration by hand, or view what the codemod will produce, see below: |
|
|
| **Before** |
|
|
| ```jsx |
| import { withAmp } from 'next/amp' |
|
|
| function Home() { |
| return <h1>My AMP Page</h1> |
| } |
|
|
| export default withAmp(Home) |
| // or |
| export default withAmp(Home, { hybrid: true }) |
| ``` |
|
|
| **After** |
|
|
| ```jsx |
| export default function Home() { |
| return <h1>My AMP Page</h1> |
| } |
|
|
| export const config = { |
| amp: true, |
| // or |
| amp: 'hybrid', |
| } |
| ``` |
|
|
| ### `next export` no longer exports pages as `index.html` |
| |
| Previously, exporting `pages/about.js` would result in `out/about/index.html`. This behavior has been changed to result in `out/about.html`. |
|
|
| You can revert to the previous behavior by creating a `next.config.js` with the following content: |
|
|
| ```js filename="next.config.js" |
| module.exports = { |
| trailingSlash: true, |
| } |
| ``` |
|
|
| ### `pages/api/` is treated differently |
|
|
| Pages in `pages/api/` are now considered [API Routes](https://nextjs.org/blog/next-9#api-routes). |
| Pages in this directory will no longer contain a client-side bundle. |
|
|
| ## Deprecated Features |
|
|
| ### `next/dynamic` has deprecated loading multiple modules at once |
|
|
| The ability to load multiple modules at once has been deprecated in `next/dynamic` to be closer to React's implementation (`React.lazy` and `Suspense`). |
|
|
| Updating code that relies on this behavior is relatively straightforward! We've provided an example of a before/after to help you migrate your application: |
|
|
| **Before** |
|
|
| ```jsx |
| import dynamic from 'next/dynamic' |
|
|
| const HelloBundle = dynamic({ |
| modules: () => { |
| const components = { |
| Hello1: () => import('../components/hello1').then((m) => m.default), |
| Hello2: () => import('../components/hello2').then((m) => m.default), |
| } |
|
|
| return components |
| }, |
| render: (props, { Hello1, Hello2 }) => ( |
| <div> |
| <h1>{props.title}</h1> |
| <Hello1 /> |
| <Hello2 /> |
| </div> |
| ), |
| }) |
|
|
| function DynamicBundle() { |
| return <HelloBundle title="Dynamic Bundle" /> |
| } |
|
|
| export default DynamicBundle |
| ``` |
|
|
| **After** |
|
|
| ```jsx |
| import dynamic from 'next/dynamic' |
|
|
| const Hello1 = dynamic(() => import('../components/hello1')) |
| const Hello2 = dynamic(() => import('../components/hello2')) |
|
|
| function HelloBundle({ title }) { |
| return ( |
| <div> |
| <h1>{title}</h1> |
| <Hello1 /> |
| <Hello2 /> |
| </div> |
| ) |
| } |
|
|
| function DynamicBundle() { |
| return <HelloBundle title="Dynamic Bundle" /> |
| } |
|
|
| export default DynamicBundle |
| ``` |
|
|
