Web mode

The renderer entry works unchanged in plain browser tabs. When window.__crossWindowState__ is absent, every state switches to a local bus:

Concern	Electron mode	Web mode
Runtime state store	main process memory	per-tab memory
Runtime cross-context sync	IPC broadcast	BroadcastChannel('cws:bus')
Storage persistence	JSON file in userData	localStorage['cws:{name}']
Storage cross-tab sync	IPC broadcast	BroadcastChannel patches
Version migration	yes (main process runs it)	version mismatch → defaults

// The same file runs in Electron windows AND plain web pages.
import { createStorageState } from "cross-window-state/renderer";

const settings = createStorageState("settings", { locale: "en" }, 1);
settings.set("locale", "zh"); // other tabs update live

Semantics you can rely on

• set() notifies the local page synchronously in both modes (the Electron main process broadcasts to every window including the writer).
• A tab that only subscribes still receives everything: the BroadcastChannel is created at module load, before any state — no missed early broadcasts.
• A tab opened later still catches up: subscribing with no local value broadcasts a hydrate request, and any live tab holding the value answers. Nothing is persisted — memory remains the only runtime store.
• localStorage failures (quota, private mode) never throw: memory state remains the source of truth for the session.
• destroy() of a runtime state is local-only on web — closing/clearing in one tab never wipes the value for its siblings (mirrors the Electron reference-count semantics).

Known differences (by design)

• No migration chain: with no main process to run one, a version mismatch resets to defaults and persists the new version.