GCounter

Increment-only counter. Ideal for page views, likes, download counts.

A GCounter is a grow-only counter. Each client tracks its own count; the total is the sum across all clients. Concurrent increments never conflict.

Usage

const views = client.gcounter("gc:page-views");

// Increment
views.increment();      // +1
views.increment(5);     // +5

// Read current value
console.log(views.value()); // number

// Subscribe to changes
const unsub = views.onChange(v => {
  console.log("views:", v);
});

// Stop listening
unsub();

API

Method	Description
increment(amount?: number)	Increment by amount (default 1, must be > 0)
value()	Returns current total
counts()	Returns raw Record<clientId, count> map
onChange(fn)	Subscribe — returns unsubscribe function

How it works

Each client maintains its own counter. The total is the sum of all per-client counters. On merge, each per-client counter takes the max of both sides — increments always win, decrements are impossible.