Get All the valid routes for a Next.js application using the app router

next-routes.ts

/**
 * Adopted from: https://github.com/Emiyaaaaa/next-routes-list/blob/8a91e25edcf7226b4534f11cfc04b39515162bf1/src/getNextRoutes.ts#L1
 */

import listPaths from 'list-paths';

export function getNextRoutes(
  src = './app',
  fileNames = ['page', 'route'],
  extensions = ['tsx', 'ts', 'js', 'jsx', 'md', 'mdx']
) {
  const pagePaths = listPaths(src, { includeFiles: true }).filter((path) => {
    const file = path.split('/').at(-1);
    const filename = file?.split('.').at(-2);
    const extension = file?.split('.').at(-1);
    if (!filename || !extension) return false;

    return extensions.includes(extension) && fileNames.includes(filename);
  });
  /**
  => paths = [
    './app/(group)/blog/page.tsx', => route should be '/blog'
    './app/(group)/blog/[...slug]/page.tsx', => route should be '/blog/[...slug]'
    './app/@component/blog/page.tsx', // should remove, because it's not a page
    './app/blog/(..)list/page.tsx', // should remove, because it's not a page
  ]
  */

  const routes = pagePaths
    .map((path) => {
      const parts = path.split(src)[1]?.split('/').filter(Boolean) ?? [];

      const url: string[] = [];

      for (let i = 0; i < parts.length; i++) {
        const part = parts[i];
        if (!part) continue;

        const isGroupRoute = part.startsWith('(') && part.endsWith(')');
        if (isGroupRoute) continue;

        const isInterceptingRoute = part.startsWith('(') && !part.endsWith(')');
        if (isInterceptingRoute) return null;

        const isParallelRoute = part.startsWith('@');
        if (isParallelRoute) return null;

        // ignore 'page.tsx' on url path
        if (i === parts.length - 1) continue;

        url.push(part);
      }

      return `/${url.join('/')}`;
    })
    .filter(Boolean) as string[];

  const unDuplicatedRoutes = Array.from(new Set(routes));

  return unDuplicatedRoutes;
}

using this code along with a script like this as a prepare script*:

import fs from 'fs';

import { getNextRoutes } from './utils/next-routes';

const routes = getNextRoutes();

const content = `export const routes = ${JSON.stringify(routes)};`;

fs.writeFileSync('all-routes.ts', content);

• This script is best to run every time the project is scaffolding, so I would like to add a prepare script in the package.json file to run it:

{
    "scripts": {
        "prepare": "npm run generate-next-routes-list",
        "generate-next-routes-list": "tsx generate-routes.ts"
   },
}

to generate a list of all valid routes in my Next.js application and use it in the middleware to detect invalid routes and redirect them to another address.