Next.js how to ignore a complete folder in app?

On next 13, app/api folder creates an error during build when nextConfig.output is "export".

In my project, I need different build type depending on environnement variable.

Any way to ignore "api" folder during build when "output" is "export" ?

When I run build with nextConfig.output as "export" I got following error:

> Export encountered errors on following paths:
/api/revalidate/route: /api/revalidate

src/app/api/revalidate/route.ts file

import { NextRequest, NextResponse } from 'next/server';
import { revalidateTag } from 'next/cache';
 
export async function GET(request: NextRequest) {
  const tag = request.nextUrl.searchParams.get('tag');
  if(tag){
    revalidateTag(tag);
  }
  return NextResponse.json({ revalidated: true, now: Date.now() });
}

Next.config.js

/** @type {import('next').NextConfig} */
const nextConfig = {
  output: process.env.NEXT_OUTPUT_MODE,
};

module.exports = nextConfig;

Reproducible repository

Here is a repository to reproduce this error
https://github.com/zeckaissue/next-export-api-crash

I found a workaround with ignore-loader. But maybe there is a better way to achieve my goal with a built-in feature of next.js

Here is my updated next.config.js

/** @type {import('next').NextConfig} */
const nextConfig = {
  output: process.env.NEXT_OUTPUT_MODE,
  /**
   *
   * @param {import('webpack').Configuration} config
   * @param {import('next/dist/server/config-shared').WebpackConfigContext} context
   * @returns {import('webpack').Configuration}
   */
  webpack: (config) => {
    if (process.env.NEXT_OUTPUT_MODE !== "export" || !config.module) {
      return config;
    }
    config.module.rules?.push({
      test: /src\/app\/api/,
      loader: "ignore-loader",
    });
    return config;
  },
};

module.exports = nextConfig;

You can use the ignore option in the Next.js configuration file (next.config.js).
You will have to create one config file if you havent already.
Open the next.config.js file and add the following code:

module.exports = {
  webpack: (config, { isServer }) => {
    if (!isServer) {
      config.module.rules.push({
        test: /YOUR FOLDER NAME\/.*/,
        loader: 'ignore-loader',
      });
}

Here is my answer.

/** @type {import('next').NextConfig} */
const nextConfig = {
  output: process.env.NEXT_OUTPUT_MODE,
  exclude: [/node_modules/, /api/], // Add this line to exclude the api folder
};

module.exports = nextConfig;