# Lesson 1 complete: when BroadcastChannel fits

Learner finished lesson 1 with all quiz answers correct. Treat as known: BroadcastChannel = same-origin named pub/sub for notify (logout, theme, invalidate); SharedWorker for shared process / one socket; sessionStorage for tab-private state; SW for network/offline; messages are signals not source of truth. Next ZPD: core API — construct by name, post/listen, sender-excluded delivery, structured clone (no transfer), close / InvalidStateError, light two-tab mental model.