A guide to implementing typescript with Next.js getStaticProps

Question

A guide to implementing typescript with Next.js getStaticProps

I have Next.js set up with the TypeScript feature enabled

Currently, I am attempting to utilize the getStaticProps function following the guidelines outlined here: https://nextjs.org/docs/basic-features/typescript

Utilizing the GetStaticProps type

export const getStaticProps: GetStaticProps = () => {
    return {
        props: {
            host: process.env.DB_HOST.toString(),
        },
    }
}

Encountering an error message like this https://i.stack.imgur.com/wxyKe.png

Type '() => { props: { host: string; }; }' is not assignable to type 'GetStaticProps<{ [key: string]: any; }, ParsedUrlQuery>'.
  Type '{ props: { host: string; }; }' is missing the following properties from type 'Promise<GetStaticPropsResult<{ [key: string]: any; }>>': then, catch, [Symbol.toStringTag], finallyts(2322)

Any assistance would be greatly appreciated.

Below is the complete code of the page:

import Head from 'next/head'
import styles from '../styles/Home.module.css'
import React from 'react'
import { GetStaticProps, GetStaticPropsContext } from 'next'

interface Props {
    host: string
}

const Home: React.FC<Props> = (props) => {
    return (
        <div className={styles.container}>
            <Head>
                <title>Create Next App</title>
                <link rel="icon" href="/favicon.ico" />
            </Head>

            <main className={styles.main}>
                aa:{props.host}
                <h1 className={styles.title}>
                    Welcome to <a href="https://nextjs.org">Next.js!</a>
                </h1>
                <p className={styles.description}>
                    Get started by editing <code className={styles.code}>pages/index.js</code>
                </p>
                <div className={styles.grid}>
                    <a href="https://nextjs.org/docs" className={styles.card}>
                        <h3>Documentation &rarr;</h3>
                        <p>Find in-depth information about Next.js features and API.</p>
                    </a>

                    <a href="https://nextjs.org/learn" className={styles.card}>
                        <h3>Learn &rarr;</h3>
                        <p>Learn about Next.js in an interactive course with quizzes!</p>
                    </a>

                    <a
                        href="https://github.com/vercel/next.js/tree/master/examples"
                        className={styles.card}
                    >
                        <h3>Examples &rarr;</h3>
                        <p>Discover and deploy boilerplate example Next.js projects.</p>
                    </a>

                    <a
                        href="https://vercel.com/import?filter=next.js&utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
                        className={styles.card}
                    >
                        <h3>Deploy &rarr;</h3>
                        <p>Instantly deploy your Next.js site to a public URL with Vercel.</p>
                    </a>
                </div>
            </main>

            <footer className={styles.footer}>
                <a
                    href="https://vercel.com?utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
                    target="_blank"
                    rel="noopener noreferrer"
                >
                    Powered by <img src="/vercel.svg" alt="Vercel Logo" className={styles.logo} />
                </a>
            </footer>
        </div>
    )
}

export const getStaticProps: GetStaticProps = () => {
    return {
        props: {
            host: process.env.DB_HOST.toString(),
        },
    }
}

export default Home

typescript next.js

Answer 1

Answer №1

I encountered the same issue and none of the solutions mentioned earlier worked for me. Upon checking the documentation, I discovered the correct approach for using getStaticProps in Next.js:

Refer to this link for more information: Next.js Documentation

The appropriate way to define getStaticProps is as follows:

import { GetStaticProps } from 'next'

export const getStaticProps: GetStaticProps = async (context) => {
  // ...
}

In your component file:

import { InferGetStaticPropsType } from 'next'
import { GetStaticProps } from 'next'

type Post = {
  author: string
  content: string
}

export const getStaticProps: GetStaticProps = async (context) => {
  const res = await fetch('https://.../posts')
  const posts: Post[] = await res.json()

  return {
    props: {
      posts,
    },
  }
}

function Blog({ posts }: InferGetStaticPropsType<typeof getStaticProps>) {
  // will resolve posts to type Post[]
}

export default Blog

This method will automatically generate the correct type for GetStaticProps in your component. It resolved the issue completely for me.

Answer 2

I encountered the same issue and none of the solutions mentioned earlier worked for me. Upon checking the documentation, I discovered the correct approach for using getStaticProps in Next.js:

Refer to this link for more information: Next.js Documentation

The appropriate way to define getStaticProps is as follows:

import { GetStaticProps } from 'next'

export const getStaticProps: GetStaticProps = async (context) => {
  // ...
}

In your component file:

import { InferGetStaticPropsType } from 'next'
import { GetStaticProps } from 'next'

type Post = {
  author: string
  content: string
}

export const getStaticProps: GetStaticProps = async (context) => {
  const res = await fetch('https://.../posts')
  const posts: Post[] = await res.json()

  return {
    props: {
      posts,
    },
  }
}

function Blog({ posts }: InferGetStaticPropsType<typeof getStaticProps>) {
  // will resolve posts to type Post[]
}

export default Blog

This method will automatically generate the correct type for GetStaticProps in your component. It resolved the issue completely for me.

Answer 3

Answer №2

Your initial example is close to being correct, but the getStaticProps function expression needs to include the async keyword. Here is a revised version for you to try:

export const getStaticProps: GetStaticProps = async () => { // must be async
  return {
    props: {
      host: process.env.DB_HOST.toString(),
    },
  };
};

This issue stems from the specific definition of getStaticProps() in Next.js, rather than TypeScript.

To enhance your example further, consider implementing type safety with the Props generic:

interface Props {
  host: string;
}

export const getStaticProps: GetStaticProps<Props> = async () => {
  return {
    props: {
      host: process.env.DB_HOST.toString(),
    },
  };
};

Answer 4

Your initial example is close to being correct, but the getStaticProps function expression needs to include the async keyword. Here is a revised version for you to try:

export const getStaticProps: GetStaticProps = async () => { // must be async
  return {
    props: {
      host: process.env.DB_HOST.toString(),
    },
  };
};

This issue stems from the specific definition of getStaticProps() in Next.js, rather than TypeScript.

To enhance your example further, consider implementing type safety with the Props generic:

interface Props {
  host: string;
}

export const getStaticProps: GetStaticProps<Props> = async () => {
  return {
    props: {
      host: process.env.DB_HOST.toString(),
    },
  };
};

Answer 5

Answer №3

The answer is provided below:

export async function getStaticProps(context): Promise<GetStaticPropsResult<HomeProps>> {
    return {
        props: {
            host: process.env.DB_HOST,
        },
    };
}

My coworker discovered the solution by referencing the GetStaticProps type definition: https://i.stack.imgur.com/ZrCiV.png

Below is the complete code for the page:

import Head from "next/head";
import styles from "../styles/Home.module.css";
import React from "react";
import { GetStaticPropsResult, GetStaticProps } from "next";

interface HomeProps {
    host: string;
}

const Home: React.FC<HomeProps> = (props: HomeProps) => {
    return (
        <div className={styles.container}>
            <Head>
                <title>Create Next App</title>
                <link rel="icon" href="/favicon.ico" />
            </Head>

            <main className={styles.main}>
                aa:{props.host}
                <h1 className={styles.title}>
                    Welcome to <a href="https://nextjs.org">Next.js!</a>
                </h1>
                <p className={styles.description}>
                    Get started by editing <code className={styles.code}>pages/index.js</code>
                </p>
                <div className={styles.grid}>
                    <a href="https://nextjs.org/docs" className={styles.card}>
                        <h3>Documentation &rarr;</h3>
                        <p>Find in-depth information about Next.js features and API.</p>
                    </a>

                    <a href="https://nextjs.org/learn" className={styles.card}>
                        <h3>Learn &rarr;</h3>
                        <p>Learn about Next.js in an interactive course with quizzes!</p>
                    </a>

                    <a href="https://github.com/vercel/next.js/tree/master/examples" className={styles.card}>
                        <h3>Examples &rarr;</h3>
                        <p>Discover and deploy boilerplate example Next.js projects.</p>
                    </a>

                    <a
                        href="https://vercel.com/import?filter=next.js&utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
                        className={styles.card}
                    >
                        <h3>Deploy &rarr;</h3>
                        <p>Instantly deploy your Next.js site to a public URL with Vercel.</p>
                    </a>
                </div>
            </main>

            <footer className={styles.footer}>
                <a
                    href="https://vercel.com?utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
                    target="_blank"
                    rel="noopener noreferrer"
                >
                    Powered by <img src="/vercel.svg" alt="Vercel Logo" className={styles.logo} />
                </a>
            </footer>
        </div>
    );
};

export async function getStaticProps(context): Promise<GetStaticPropsResult<HomeProps>> {
    return {
        props: {
            host: process.env.DB_HOST,
        },
    };
}

export default Home;

Answer 6

The answer is provided below:

export async function getStaticProps(context): Promise<GetStaticPropsResult<HomeProps>> {
    return {
        props: {
            host: process.env.DB_HOST,
        },
    };
}

My coworker discovered the solution by referencing the GetStaticProps type definition: https://i.stack.imgur.com/ZrCiV.png

Below is the complete code for the page:

import Head from "next/head";
import styles from "../styles/Home.module.css";
import React from "react";
import { GetStaticPropsResult, GetStaticProps } from "next";

interface HomeProps {
    host: string;
}

const Home: React.FC<HomeProps> = (props: HomeProps) => {
    return (
        <div className={styles.container}>
            <Head>
                <title>Create Next App</title>
                <link rel="icon" href="/favicon.ico" />
            </Head>

            <main className={styles.main}>
                aa:{props.host}
                <h1 className={styles.title}>
                    Welcome to <a href="https://nextjs.org">Next.js!</a>
                </h1>
                <p className={styles.description}>
                    Get started by editing <code className={styles.code}>pages/index.js</code>
                </p>
                <div className={styles.grid}>
                    <a href="https://nextjs.org/docs" className={styles.card}>
                        <h3>Documentation &rarr;</h3>
                        <p>Find in-depth information about Next.js features and API.</p>
                    </a>

                    <a href="https://nextjs.org/learn" className={styles.card}>
                        <h3>Learn &rarr;</h3>
                        <p>Learn about Next.js in an interactive course with quizzes!</p>
                    </a>

                    <a href="https://github.com/vercel/next.js/tree/master/examples" className={styles.card}>
                        <h3>Examples &rarr;</h3>
                        <p>Discover and deploy boilerplate example Next.js projects.</p>
                    </a>

                    <a
                        href="https://vercel.com/import?filter=next.js&utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
                        className={styles.card}
                    >
                        <h3>Deploy &rarr;</h3>
                        <p>Instantly deploy your Next.js site to a public URL with Vercel.</p>
                    </a>
                </div>
            </main>

            <footer className={styles.footer}>
                <a
                    href="https://vercel.com?utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
                    target="_blank"
                    rel="noopener noreferrer"
                >
                    Powered by <img src="/vercel.svg" alt="Vercel Logo" className={styles.logo} />
                </a>
            </footer>
        </div>
    );
};

export async function getStaticProps(context): Promise<GetStaticPropsResult<HomeProps>> {
    return {
        props: {
            host: process.env.DB_HOST,
        },
    };
}

export default Home;

Answer 7

Answer №4

In the year 2022, the most effective method is to utilize generics in the types of Next.js.

import type { NextPage, GetStaticProps } from "next";
// ...

interface HomePageProps {
  host: string
}

const HomePage: NextPage<HomePageProps> = (props) => {
  // ...
};

export const getStaticProps: GetStaticProps<HomePageProps> = async () => {
  // ...
};

Answer 8

In the year 2022, the most effective method is to utilize generics in the types of Next.js.

import type { NextPage, GetStaticProps } from "next";
// ...

interface HomePageProps {
  host: string
}

const HomePage: NextPage<HomePageProps> = (props) => {
  // ...
};

export const getStaticProps: GetStaticProps<HomePageProps> = async () => {
  // ...
};

Answer 9

Answer №5

Disclaimer: This code snippet is intended for use in setting up pages only.

Here is a concise way to achieve constant reuse:


export const getStaticProps = async ({
    params,
}: GetStaticPropsContext<PageParams>): Promise<
    GetStaticPropsResult<ContentPageProps>
> => {
    const { title, description } = await fetch(".../entity", { uuid: params.uuid })
    return {
        props: {
            title,
            description,
        },
    }
}

This is an example of the correct typing for getStaticProps in page/content.tsx:

import type {
    GetStaticPathsResult,
    GetStaticPropsContext,
    GetStaticPropsResult,
} from 'next'

type PageParams = {
   uuid: string
}

type ContentPageProps = {
   title: string
   description: string
}

const ContentPage = ({ title, description }: ContentPageProps): JSX.Element => {
    return (
        <>
             <h1>{title}</h1>
             <p>{description}</p>
        </>
    )
}

export default ContentPage

export const getStaticProps = async ({
    params,
}: GetStaticPropsContext<PageParams>): Promise<
    GetStaticPropsResult<ContentPageProps>
> => {
    const { title, description } = await fetch(".../entity", { uuid: params.uuid })
    return {
        props: {
            title,
            description,
        },
    }
}

export const getStaticPaths = async ({}): Promise<
    GetStaticPathsResult<PageParams>
> => {
    return {
        paths: { params: { uuid: "54b659a1-3f20-4440-90b5-9107bd62b5ca" }},
        fallback: false,
    }
}

Key point to note:

async (context:GetStaticPropsContext<PageParams>):
    Promise<GetStaticPropsResult<ContentPageProps>

In this context, PageParams is based on ParsedUrlQuery, and ContentPageProps represents what you will use in your component for rendering purposes, with potential complexity but without recursion.

Answer 10

Disclaimer: This code snippet is intended for use in setting up pages only.

Here is a concise way to achieve constant reuse:


export const getStaticProps = async ({
    params,
}: GetStaticPropsContext<PageParams>): Promise<
    GetStaticPropsResult<ContentPageProps>
> => {
    const { title, description } = await fetch(".../entity", { uuid: params.uuid })
    return {
        props: {
            title,
            description,
        },
    }
}

This is an example of the correct typing for getStaticProps in page/content.tsx:

import type {
    GetStaticPathsResult,
    GetStaticPropsContext,
    GetStaticPropsResult,
} from 'next'

type PageParams = {
   uuid: string
}

type ContentPageProps = {
   title: string
   description: string
}

const ContentPage = ({ title, description }: ContentPageProps): JSX.Element => {
    return (
        <>
             <h1>{title}</h1>
             <p>{description}</p>
        </>
    )
}

export default ContentPage

export const getStaticProps = async ({
    params,
}: GetStaticPropsContext<PageParams>): Promise<
    GetStaticPropsResult<ContentPageProps>
> => {
    const { title, description } = await fetch(".../entity", { uuid: params.uuid })
    return {
        props: {
            title,
            description,
        },
    }
}

export const getStaticPaths = async ({}): Promise<
    GetStaticPathsResult<PageParams>
> => {
    return {
        paths: { params: { uuid: "54b659a1-3f20-4440-90b5-9107bd62b5ca" }},
        fallback: false,
    }
}

Key point to note:

async (context:GetStaticPropsContext<PageParams>):
    Promise<GetStaticPropsResult<ContentPageProps>

In this context, PageParams is based on ParsedUrlQuery, and ContentPageProps represents what you will use in your component for rendering purposes, with potential complexity but without recursion.

Answer 11

Answer №6

Dealing with the same challenge as the original poster, I found a helpful tutorial that solved my issue: . The tutorial specifically tackled the problem associated with getStaticPaths requiring a type of ParsedUrlQuery. The author suggests extending it as a solution and emphasizes the importance of naming properties accurately to avoid TypeScript errors.

Answer 12

Dealing with the same challenge as the original poster, I found a helpful tutorial that solved my issue: . The tutorial specifically tackled the problem associated with getStaticPaths requiring a type of ParsedUrlQuery. The author suggests extending it as a solution and emphasizes the importance of naming properties accurately to avoid TypeScript errors.

Answer 13

Answer №7

fetchData

export const fetchData: FetchData = async () => {

fetchDataProps

export const fetchDataProps = async ({data}: 
                                     FetchDataPropsContext<{ id: number }>) => {

DataComponent

 export default function DataComponent({data}: InferFetchDataPropsType<typeof fetchDataProps>) {

Answer 14

fetchData

export const fetchData: FetchData = async () => {

fetchDataProps

export const fetchDataProps = async ({data}: 
                                     FetchDataPropsContext<{ id: number }>) => {

DataComponent

 export default function DataComponent({data}: InferFetchDataPropsType<typeof fetchDataProps>) {

A guide to implementing typescript with Next.js getStaticProps

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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