Incorrect type for Promise: the Promise did not resolve to 'Response'.

export default {
  fetch: async (request: Request, env: Env, context: Context) => {
    context.slack = new Slack(env.SLACK_APP_BOT_TOKEN);
    context.waitUntil(router.handle(request, env, context));
  },
};

export default {
  fetch: async (request: Request, env: Env, context: Context) => {
    context.slack = new Slack(env.SLACK_APP_BOT_TOKEN);
    context.waitUntil(router.handle(request, env, context));
  },
};