Initial Commit

packages/networking/events/broadcast-channel/src/channel/heartbeat.ts

@@ -0,0 +1,44 @@
+/**
+ * Lightweight pair of `setInterval` timers managing the heartbeat / cleanup
+ * cadence of a `TypedBroadcastChannel`. Extracted from `channel.ts` so the
+ * channel core stays under the 300-line hard budget while keeping each timer
+ * lifecycle visible and individually testable.
+ */
+export interface HeartbeatRunnerOptions {
+    readonly heartbeatInterval: number;
+    readonly onHeartbeat: () => void;
+    readonly onCleanup: () => void;
+}
+
+/** Mutable pair of timers; `start` schedules, `stop` clears. */
+export class HeartbeatRunner {
+    private readonly opts: HeartbeatRunnerOptions;
+    private heartbeatTimer: ReturnType<typeof setInterval> | null = null;
+    private cleanupTimer: ReturnType<typeof setInterval> | null = null;
+
+    public constructor(opts: HeartbeatRunnerOptions) {
+        this.opts = opts;
+    }
+
+    public start(): void {
+        this.heartbeatTimer = setInterval(
+            () => this.opts.onHeartbeat(),
+            this.opts.heartbeatInterval
+        );
+        this.cleanupTimer = setInterval(
+            () => this.opts.onCleanup(),
+            this.opts.heartbeatInterval * 2
+        );
+    }
+
+    public stop(): void {
+        if (this.heartbeatTimer !== null) {
+            clearInterval(this.heartbeatTimer);
+            this.heartbeatTimer = null;
+        }
+        if (this.cleanupTimer !== null) {
+            clearInterval(this.cleanupTimer);
+            this.cleanupTimer = null;
+        }
+    }
+}