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Callbacks and Delegates​

Additional Information​

onReady is the single API for session tracking. It supports two call patterns:

Promise (all architectures)​

Resolves once when FullStory has initialized and started session capture.

ES6​

FullStory.onReady().then(function (result) {
  const replayStartUrl = result.replayStartUrl;
  const replayNowUrl = result.replayNowUrl;
  const sessionId = result.sessionId;
});

async/await​

const { replayStartUrl, replayNowUrl, sessionId } = await FullStory.onReady();

Listener (New Architecture only)​

Subscribes to every session start. The callback fires immediately if a session is already active, and again for each subsequent session. Returns a subscription object with a remove method to unsubscribe.

const subscription = FullStory.onReady(function (result) {
  const replayStartUrl = result.replayStartUrl;
  const replayNowUrl = result.replayNowUrl;
  const sessionId = result.sessionId;
});

// Later, to unsubscribe:
subscription.remove();
note

The listener overload onReady(callback) is only supported on the New Architecture. On the Old Architecture, calling onReady with a callback logs a warning and returns a no-op subscription. Use the Promise-based API for compatibility across both architectures.