如何将 next.js 中的 pageProps 从子组件传递给 _app.js？

Question

I'm working on a next.js app and my page layout is going through the following hierarchy:

  _app.js
     Page.js
         Header.js
         PageContent.js

I need to pass some parameters from PageContent to Header without using redux.

Inside _app.js I have the following:

class Main extends App {
  render() {
  const {
    Component,
    pageProps,
    apollo,
    router: { route }
  } = this.props;

 return (
  <ApolloProvider client={apollo}>
      <Page
        pathname={route.split("/")[1]}
        {...pageProps}
        localLinks={Component.LocalLinks}
        render={props => <Component {...props} />}
      />
   </ApolloProvider>
  );
 }
}

I'm assuming there should be a way to pass some propse (pageProps) from PageContent to _app and pass that down to Page and make them accessible to header. Is there a next.js specific trick here that I'm not familiar with?

Answer 1

Here's a full example with contexts (approach previously suggested in this other answer by slightly modifying https://github.com/vercel/next.js/tree/7df7c5e80515eea6745fd59e54d87e5ee709fe0c/examples/with-app-layout tested on Next.js 12.0.7 and React 17:

pages/_app.js

import React from 'react'

export const MyAppContext = React.createContext({
  n: 0,
  setN: undefined,
});

function Header(props) {
  return <div>n = { props.n }</div>
}

export default function App({ Component, pageProps }) {
  const [n, setN] = React.useState(0)
  return (
    <MyAppContext.Provider value={{n, setN}}>
      <Header n={n} />
      <Component {...pageProps} />
    </MyAppContext.Provider>
  )
}

pages/index.js

import { MyAppContext } from './_app.js'
import React from 'react'

export default function Home() {
  const {n, setN} = React.useContext(MyAppContext)
  setN(new Date().getTime())
  return <div>test</div>
}

If it's something that depends only on the page and not props

The following works without contexts, I wonder if setting such attributes could cause any problems down the line:

pages/_app.js

function Header(props) {
  return <div>n = { props.n }</div>
}

export default function App({ Component, pageProps }) {
  return (
    <>
      <Header n={Component.n} />
      <Component {...pageProps} />
    </>
  )
}

pages/index.js

export default function Home() {
  return <div>test</div>
}
Home.n = 1

Answer 2

You can use context api or Parent container state (here Page component).

First Way -> Use context api

Second Way

• make State on page component
• pass StatemodifierFunction props to pageContent
• then modify state by calling this StatemodifierFunction
• then pass this state to Header Component

** Third way **

• you can use react node also