What Is the Purpose of the getStaticPaths Function in Next.js?

The getStaticPaths function in Next.js is used to generate static pages for dynamic routes during the build process. It allows you to specify which dynamic routes should be pre-rendered ahead of time based on a list of paths.

In Next.js, dynamic routes are defined using square brackets in filenames (e.g., [ID].js), which creates routes like user/[ID]. The getStaticPaths function enables you to pre-generate static pages for each of these routes by returning an object containing two properties:

• paths: An array of objects specifying the dynamic parameters for each route to be pre-rendered.
• fallback: Determines how Next.js should handle paths not included in the paths array. It can be:
• false: Returns a 404 page for undefined paths.
• true: Generates the page on-demand if a requested path is not pre-rendered.

Here’s a basic example of how getStaticPaths is used:

export async function getStaticPaths() {
    // Define the paths to pre-render
    const paths = [
        { params: { id: '1' } },
        { params: { id: '2' } },
        { params: { id: '3' } }
    ];
    return {
        paths,
        fallback: false
    };
}

The above setup will pre-render static pages for user/1, user/2, and user/3 at build time.