Chrome Tab Events: Build a Reliable Lifecycle Tracker

Know what each event answers

tabs.onCreated reports a new tab, but Chrome warns that the URL may not yet be set. tabs.onUpdated reports changed fields such as status, URL, title or groupId. tabs.onActivated reports a tab becoming active within its window. tabs.onRemoved reports closure and includes the window ID and whether the window itself is closing.

These are different facts. Activation does not prove a navigation completed, and an update does not necessarily mean a new page. Use the event that matches the question your feature is asking.

• Chrome Tabs API events

Register listeners at service-worker startup

Manifest V3 service workers are event-driven and can be terminated after inactivity. Register chrome.tabs.onCreated.addListener and other listeners at the top level of the worker, where Chrome can restore event handling when the worker wakes. Do not rely on a global array as the only record of previously seen tabs.

Chrome normally stops an idle extension service worker after 30 seconds. State that persists beyond a wake cycle belongs in an appropriate storage area, while transient calculations can be rebuilt from chrome.tabs.query().

• Chrome extension service-worker lifecycle

Reconcile instead of trusting one event stream

At startup, query the current tabs and build a fresh map keyed by tab id. Then apply events to keep the map current. After a worker restart or unexpected gap, run another query and reconcile. This protects against stale assumptions when the extension was unloaded or updated.

Store durable project links by URL and your own record ID, not by the tab ID alone. Tab IDs are unique only within a browser session. A saved note must remain meaningful even after the browser restarts and assigns different IDs.

Guard against noisy updates

onUpdated can fire for several properties during one navigation. Check changeInfo for the field you care about before doing expensive work. For a title index, update only when changeInfo.title is present. For a page-ready action, also consider status and whether the URL you intend to process is allowed.

Avoid writing a new storage record for every minor update. Batch or debounce changes and compare with the prior value. This reduces unnecessary work and avoids exhausting storage write limits.

• Chrome storage API limits and events

Idea: a tab timeline the user can understand

Build an opt-in local timeline that records only meaningful transitions: a project tab opened, moved to a group, or closed after its link was saved. Show what was actually observed and avoid claiming to reconstruct page contents from a URL.

A simple timeline can help people resume a paused task and diagnose an accidental close. Give them a way to clear it, and describe the retention period plainly.

Test event races

Open a blank tab that navigates immediately, drag a tab between windows, close a whole window and restart the extension worker. Compare the final map with a fresh tabs.query() result after each scenario.

If the final state differs, fix reconciliation before adding more event handlers. A reliable tracker is measured by the state it recovers, not by how many callbacks it logs.