Next.js Data Fetching Methods

Next.js offers several data fetching methods that allow developers to retrieve data before displaying the page to the user. This enables faster loading times and a better user experience.

Syntax

Next.js data fetching methods can be defined as async functions that return data.

getStaticProps()

export async function getStaticProps(context) {
  const res = await fetch('https://api.example.com/posts');
  const posts = await res.json();

  return {
    props: {
      posts
    }
  }
}

getServerSideProps()

export async function getServerSideProps(context) {
  const res = await fetch(`https://api.example.com/posts/${context.params.id}`);
  const post = await res.json();

  return {
    props: {
      post
    }
  }
}

getInitialProps()

Index.getInitialProps = async (context) => {
  const res = await fetch('https://api.example.com/posts');
  const posts = await res.json();

  return { posts }
}

Example

import React from 'react'

const Posts = ({ posts }) => (
  <ul>
    {posts.map(post => (
      <li key={post.id}>
        {post.title}
      </li>
    ))}
  </ul>
)

export async function getStaticProps() {
  const res = await fetch('https://api.example.com/posts')
  const posts = await res.json()

  return {
    props: {
      posts,
    },
  }
}

export default Posts

Output

The above example would output a list of posts fetched from an API.

Explanation

Next.js data fetching methods allow developers to retrieve data before the page is rendered, improving the user experience by reducing the load time. getStaticProps() retrieves the data at build time and can be used with static sites, while getServerSideProps() retrieves the data at request time and can be used with server-rendered pages. The getInitialProps() method is used with server-rendered pages and is called on both the server and client side.

Use

Next.js data fetching methods are ideal for retrieving data for pages that require static data or for pages that require data that may change regularly and should always be up-to-date.

Important Points

• Data fetching methods can be defined on a per-page basis.
• getStaticProps() is used for static sites where data only changes at build time.
• getServerSideProps() is used for pages where data changes frequently and needs to be up-to-date.
• getInitialProps() is used for server-rendered pages and is called on both the server and client side.
• Data fetching methods are necessary for ensuring fast loading times and a good user experience.

Summary

Next.js data fetching methods are an important part of building fast, modern web applications. By retrieving data before the page is rendered, developers can improve the user experience by reducing load times and ensuring that data is always up-to-date. Understanding the syntax, use cases, and important points for each method is critical to building efficient, scalable applications.