【Nextjs】Layoutとは

レイアウトファイル

import Navbar from './navbar'
import Footer from './footer'
 
export default function Layout({ children }) {
  return (
    <>
      <Navbar />
      <main>{children}</main>
      <Footer />
    </>
  )
}

_app.tsx

import type { ReactElement, ReactNode } from 'react'
import type { NextPage } from 'next'
import type { AppProps } from 'next/app'
 
export type NextPageWithLayout<P = {}, IP = P> = NextPage<P, IP> & {
  getLayout?: (page: ReactElement) => ReactNode
}
 
type AppPropsWithLayout = AppProps & {
  Component: NextPageWithLayout
}
 
export default function MyApp({ Component, pageProps }: AppPropsWithLayout) {
  // Use the layout defined at the page level, if available
  const getLayout = Component.getLayout ?? ((page) => page)
 
  return getLayout(<Component {...pageProps} />)
}

ページごとのindex.tsx

import type { ReactElement } from 'react'
import Layout from '../components/layout'
import NestedLayout from '../components/nested-layout'
import type { NextPageWithLayout } from './_app'
 
const Page: NextPageWithLayout = () => {
  return <p>hello world</p>
}
 
Page.getLayout = function getLayout(page: ReactElement) {
  return (
    <Layout>
      <NestedLayout>{page}</NestedLayout>
    </Layout>
  )
}
 
export default Page

注意点

• getLayoutで囲うのはだけ。
• 他にProviderなどがある場合は、getLayoutを囲う。
  <Provider>{getLayout(<Components />)}</Provider>のような感じ。