Next.js Codemods

Next.js provides Codemod transformations to help upgrade your Next.js codebase when a feature is deprecated.

Codemods are transformations that run on your codebase programmatically. This allows for a large amount of changes to be applied without having to manually go through every file.

Usage

npx @next/codemod <transform> <path>

• transform - name of transform, see available transforms below.
• path - files or directory to transform
• --dry Do a dry-run, no code will be edited
• --print Prints the changed output for comparison

Next.js 9

name-default-component

Transforms anonymous components into named components to make sure they work with Fast Refresh.

For example

// my-component.js
export default function () {
  return <div>Hello World</div>
}

Transforms into:

// my-component.js
export default function MyComponent() {
  return <div>Hello World</div>
}

The component will have a camel cased name based on the name of the file, and it also works with arrow functions.

Usage

Go to your project

cd path-to-your-project/

Run the codemod:

npx @next/codemod name-default-component

withamp-to-config

Transforms the withAmp HOC into Next.js 9 page configuration.

For example:

// Before
import { withAmp } from 'next/amp'
function Home() {
  return <h1>My AMP Page</h1>
}
export default withAmp(Home)

// After
export default function Home() {
  return <h1>My AMP Page</h1>
}
export const config = {
  amp: true,
}

Usage

Go to your project

cd path-to-your-project/

Run the codemod:

npx @next/codemod withamp-to-config

Next.js 6

url-to-withrouter

Transforms the deprecated automatically injected url property on top level pages to using withRouter and the router property it injects. Read more here: err.sh/next.js/url-deprecated

For example:

// From
import React from 'react'
export default class extends React.Component {
  render() {
    const { pathname } = this.props.url
    return <div>Current pathname: {pathname}</div>
  }
}

// To
import React from 'react'
import { withRouter } from 'next/router'
export default withRouter(
  class extends React.Component {
    render() {
      const { pathname } = this.props.router
      return <div>Current pathname: {pathname}</div>
    }
  }
)

This is just one case. All the cases that are transformed (and tested) can be found in the __testfixtures__ directory.

Usage

Go to your project

cd path-to-your-project/

Run the codemod:

npx @next/codemod url-to-withrouter