Pass a server-side prop to a client-side component

Question

I am trying to figure out how to pass a variable declared on the server side of my nextjs 13 app into a client side function that I have declared in one of my component files. As you can see in my code I am trying to pass the 'x' variable into the Props function which is part of the client side component. I am trying to console log the variable passed into the Props function to see if the variable is passed correctly. but it is returning as 'undefined'. Can someone explain to me how I can pass this variable? Note: I know in this current example it is not necessary for my component to be on the client side. I am just providing this code as an example to answer my question.

Server-side code:

import Props from "./Components/props"

export default function Home() {
  const x = 'hello'

  return (
    <main>
      <Props data = {x} />
      <p>Hello</p>
    </main>
  )
}

Client-side code:

"use client"

export default function Props({ data }) {
    console.log(data);

    return (
        <p>Test</p>
      );
    };

Error:

error - SyntaxError: Unexpected token u in JSON at position 0
    at JSON.parse (<anonymous>)

Controvert

Your example should already work since 'hello' is a string which is serializable. Have you tried directly inserting the string, as in data={'hello'}? – Staphylorrhaphy

Was this issue solved somehow? I'm also interested .. – Isbell

Answer 1

Next.js version ^13 is based on an extensive use of Memoization and the fetch API. You can fetch multiple times without having a performance issue.

following Next.js doc:

Instead of using React Context (which is not available on the server) or passing data as props, you can use fetch or React's cache function to fetch the same data in the components that need it, without worrying about making duplicate requests for the same data. This is because React extends fetch to automatically memoize data requests, and the cache function can be used when fetch is not available.

So, you were passing props from a component to another. Now, fetch once (setting the request to be cached) is the base server component to request as early as possible, and request a second time in the client component, without losing performance.

hope you find this well, and that it helps you.

Broomstick

Answer 2

Props passed from the Server to Client Components need to be serializable

That might be a reason

https://nextjs.org/docs/getting-started/react-essentials#passing-props-from-server-to-client-components-serialization

Szczecin

Is good to refer about references to show definitions but the core of the question is how to serialize it. Your answer look imcomplete and doenst provide a solution. – Forbidden

sorry, but in the question there is no 'how to serialize' – Szczecin

"how I can pass this variable?" implicitly asks for full instructions how to achieve the goal, which includes how to do the steps needed (such as 'how to serialize'), so yes your answer doesn't provide a solution, and neither does Vercel's docs unfortunately. – Staphylorrhaphy

Sorry for being so late, I was too busy. From server page to client page I simply pass props like I do for any component <ClientPage props={dataFromServerPage} />. If you found any better looking solution please tell me. – Szczecin

Answer 3

Whenever you want to pass data from server-side to client side, you need to return an object containing a key:value pair of the data you want to pass to the client-side. It will be accessible to you via the props object.

Server-Side

export const getServerSideProps = async () {
  const x = 'hello';
  return {
    x
  }
}

Client-Side

export const Home = async (props) => {
  console.log(props.x);
}

Bridgework