Server-side state passing in NextJS - Step-by-Step Execution

Concept Flow - Server-side state passing

User requests page

↓

Server runs server component

↓

Fetch or compute data on server

↓

Pass data as props to client component

↓

Client component renders with data

↓

User sees page with server data

The server receives a request, runs server code to get data, then passes that data to client components for rendering.

Execution Sample

NextJS

export default async function Page() {
  const res = await fetch('https://api.example.com/data');
  const data = await res.json();
  return <ClientComponent data={data} />;
}

'use client';

function ClientComponent({ data }) {
  return <div>{data.message}</div>;
}

This code fetches data on the server, then passes it as a prop to a client component that renders it.

Execution Table

Step	Action	Data State	Component Rendered	Output
1	User requests page	No data yet	No component	Loading...
2	Server fetches data	data = { message: 'Hello from server' }	No component	Loading...
3	Server renders Page component	data passed as prop	Page renders ClientComponent	<div>Hello from server</div>
4	Client receives rendered HTML	data present in props	ClientComponent hydrated	<div>Hello from server</div>
5	User sees page	data displayed	ClientComponent visible	Hello from server

💡 Rendering completes after server data is passed and client component renders with it.

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
data	undefined	{ message: 'Hello from server' }	{ message: 'Hello from server' }	{ message: 'Hello from server' }

Key Moments - 3 Insights

Why does the server fetch data before rendering the component?

Because the server component runs first and needs data to pass as props to the client component, as shown in step 2 and 3 of the execution table.

How does the client component get the server data?

The server passes the fetched data as props to the client component during rendering, so the client component receives it ready to display, as seen in step 3.

Why is the user not seeing 'Loading...' after the server fetch?

Because the server waits for data before rendering and sending HTML, so the user only sees the final rendered output, not intermediate loading states.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of 'data' after step 2?

A null

B { message: 'Hello from server' }

C undefined

D {}

💡 Hint

Check the 'Data State' column in step 2 of the execution table.

At which step does the ClientComponent first render with data?

A Step 3

B Step 1

C Step 4

D Step 5

💡 Hint

Look at the 'Component Rendered' column to see when ClientComponent renders.

If the server fetch fails and returns no data, what would change in the execution table?

A User would see the final output as normal

B ClientComponent would render with data anyway

C Data State at step 2 would be undefined or error

D Step 3 would be skipped

💡 Hint

Consider what happens if fetch does not return data at step 2.

Concept Snapshot

Server-side state passing in Next.js:
- Server components fetch or compute data first
- Data passed as props to client components
- Client components render with server data
- User sees fully rendered page with data
- No loading state on initial load

Full Transcript

In Next.js, when a user requests a page, the server runs the server component first. This server component fetches or computes the needed data. Once the data is ready, it passes it as props to client components. The client components then render using this data. The user receives a fully rendered page with the server data included, so they do not see loading states. This flow ensures fast, data-ready pages on first load.