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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.

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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();

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API

MethodDescription
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
stream()Returns an Effect Stream<number> that emits on every change

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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.