export function subscribeToStateChanges()

in src/common/quick_chat/utils.ts [119:165]

• 39 lines of code
• 5 McCabe index (conditional complexity)

export function subscribeToStateChanges({
  actorTitle,
  actor,
  callback,
}: {
  actorTitle: string;
  actor: Actor<UnknownActorLogic>;
  callback?: (snapshot: { value: unknown }) => void;
}) {
  let previousState = actor.getSnapshot().value;

  const subscription = actor.subscribe(snapshot => {
    if (previousState !== snapshot.value) {
      if (typeof previousState === 'string') {
        log.debug(`[${actorTitle}]: state changed from "${previousState}" to "${snapshot.value}"`);
      } else {
        // if actor is a parallel state machine, state is returned as an object
        const stateChangeLines: string[] = [];
        const allKeys = [
          ...new Set([...Object.keys(previousState), ...Object.keys(snapshot.value)]),
        ];
        allKeys.forEach(key => {
          const prevValue = previousState[key];
          const currentValue = snapshot.value[key];

          // Only show properties that changed
          if (prevValue !== currentValue) {
            stateChangeLines.push(`[${key}]: "${prevValue}" to "${currentValue}"`);
          }
        });
        if (stateChangeLines.length > 0) {
          const formattedChanges = stateChangeLines.join(',\n');
          log.debug(`[${actorTitle}]: State changes: ${formattedChanges}`);
        }
      }

      previousState = snapshot.value;

      callback?.(snapshot);
    }
  });

  // return a function to unsubscribe
  return () => {
    subscription.unsubscribe();
  };
}