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Callbacks and Delegates​

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.

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.

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.

Additional Information​