index/classes/PendingSubscriptionTracker.md

Pending Subscription Tracker

Tracks pending subscriptions with timeout guards. Prevents memory leaks from subscriptions that never complete. Used when subscribing to streams where confirmation is required from the server.

Features:

• Automatic timeout handling
• Memory leak prevention (clears expired pending)
• Tracks pending duration
• Fast O(1) checks

Example

// Test case: Pending subscription tracking with timeouts
const tracker = new PendingSubscriptionTracker();

// Add pending subscription with 1 second timeout
tracker.addPending('sub-123', 1000);
console.assert(tracker.isPending('sub-123') === true);
console.assert(tracker.getPendingCount() === 1);

// Mark as completed (timeout won't fire)
tracker.removePending('sub-123');
console.assert(tracker.isPending('sub-123') === false);

// Check if subscription timed out
tracker.addPending('sub-456', 100);
await new Promise(r => setTimeout(r, 200)); // Wait for timeout
tracker.clearExpired(); // Manual cleanup
console.assert(tracker.isPending('sub-456') === false);

// Multiple pending subscriptions
tracker.addPending('sub-a', 1000);
tracker.addPending('sub-b', 1000);
tracker.addPending('sub-c', 1000);
console.assert(tracker.getPendingCount() === 3);

Since

6.6.0

Constructors

Constructor

new PendingSubscriptionTracker(): PendingSubscriptionTracker

Returns

PendingSubscriptionTracker

Methods

addPending()

addPending(id, timeoutMs): void

Add a pending subscription with timeout

Parameters

Parameter	Type	Description
id	string	Subscription identifier (e.g., token name)
timeoutMs	number	Timeout duration in milliseconds

Returns

void

---

clear()

clear(): void

Clear all pending subscriptions

Returns

void

---

clearExpired()

clearExpired(): void

Manually clear expired pending subscriptions

Normally called automatically by the timeout, but can be called explicitly for cleanup.

Returns

void

---

getPendingCount()

getPendingCount(): number

Get count of pending subscriptions

Returns

number

Number of subscriptions currently pending

---

isPending()

isPending(id): boolean

Check if a subscription is pending

Parameters

Parameter	Type	Description
id	string	Subscription identifier to check

Returns

boolean

True if subscription is still pending

---

removePending()

removePending(id): void

Remove a pending subscription (e.g., when it completes or is cancelled)

Parameters

Parameter	Type	Description
id	string	Subscription identifier to remove

Returns

void