NextJS Amplitude Cookie Example

[smol-honk]

Summary

Noticed that there is a section on accessing amplitude cookies in the docs: https://www.docs.developers.amplitude.com/experiment/sdks/nodejs-sdk/#access-amplitude-cookies

Do we need to add that to the examples NextJS app or does the sdk handle that automatically?

Motivations

Would like to know if it's suggested to add middleware to NextJS apps using SSR for experiments.

[cjcheshire]

I was trying to do something like this

import type { NextRequest } from 'next/server';
import { NextResponse } from 'next/server';
import { generate } from 'src/middleware/amplitude-utils';

export function middleware(request: NextRequest) {
  const ampValue = request.cookies.get(amplitudeCookieName)?.value;

  const response = NextResponse.next();

  if (!ampValue) {
    const deviceId = randomString(32);
    const newAmpValue = AmplitudeCookie.generate(deviceId, true);
    response.cookies.set(amplitudeCookieName, newAmpValue);
  }

  return response;
}

Sadly nextjs does not like this Error: The edge runtime does not support Node.js 'https' module…

I would love to lean on the generate method from the module just in case the api changes. The only workaround I could have is to copy the method directly from the module.

We have multiple apps, so this ideally would be moved to a lambda to share across all of them, again concerns around ensuring consistency with the cookie shape.

@smol-honk - any thoughts?