I dont think GrowthBook has some internal way to make this easier

current code in case helpful:

// Function to retrieve a cookie's value by name
  function getCookie(name) {
    const match = document.cookie.match(new RegExp('(^| )' + name + '=([^;]+)'));
    return match ? decodeURIComponent(match[2]) : null;
  }

  // Function to configure GrowthBook with attributes including the anonymousId
  function configGrowthbook(anonymousId) {
    window.growthbook_config = window.growthbook_config || {};
    window.growthbook_config.attributes = { anonymousId };
    console.log("Configured GrowthBook with Anonymous ID:", anonymousId);
  }

  // Try to initialize GrowthBook with the anonymous ID from the cookie
  const anonymousIdFromCookie = getCookie("ajs_anonymous_id");
  if (anonymousIdFromCookie) {
    configGrowthbook(anonymousIdFromCookie);
  } else {
    // Wait for analytics to be ready if the cookie is not found
    console.log("Anonymous ID cookie not found, waiting for analytics...");
    analytics.ready(function() {
      const analyticsAnonymousId = analytics.user().anonymousId();
      if (analyticsAnonymousId) {
        configGrowthbook(analyticsAnonymousId);
      } else {
        console.error("Failed to retrieve Anonymous ID after analytics ready.");
      }
    });
  }

<script async="" data-api-host="<https://cdn.growthbook.io>" data-client-key="sdk-xEb0AZIn228345Oj" src="<https://cdn.jsdelivr.net/npm/@growthbook/growthbook/dist/bundles/auto.min.js>">
</script>

Alright, actually it turned out to be something entirely different. Maybe this will help out others - might also be nice for growthbook to handle this under the hood or add to the docs. We use Segment for tracking. In order for it to really work with Segment, GB needs the anonymous ID from Segment. To get it, you have a few options. You can look for the

ajs_anonymous_id

cookie / local storage value and grab it or use the

analytics.user().anonymousId()

method to get it. The using the latter method, however, won't work until Segment is initialized. Typically, you can use the

analytics.ready(function() { Logic Here })

call back to make sure you're going to be able to get an anonymous id, but if the user is using an ad blocker and Segment is loading client side destinations - chances are those libraries will fail to load and thus the ready callback will never happen (this also happens with Rudderstack btw). So, our solution was to check for the cookie and then generate our own UUID and pass it to Segment as our own Anonymous ID like so

analytics.user().anonymousId(anonymousId);

Anyway, this was not intuitive and so maybe worth investigating further / mentioning in the docs or handling in the SDK so folks don't have to roll their own code to make GB work when using Segment, Rudderstack, etc