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An ORSet (Observed-Remove Set) allows concurrent adds and removes without conflicts. Each add generates a unique tag; a remove only removes the specific tags it observed — so a concurrent add of the same element wins.

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Usage without schema

const tags = client.orset("or:article-123-tags");

tags.add("typescript");
tags.remove("javascript");

console.log(tags.values()); // Set<unknown>

tags.onChange(set => console.log("tags:", set));

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Usage with schema

import { Schema } from "effect";

const Item = Schema.Struct({ id: Schema.String, name: Schema.String });
const cart = client.orset("or:cart-user-42", Item);

cart.add({ id: "prod-1", name: "Keyboard" });

cart.onChange(items => {
  // items: Set<{ id: string; name: string }>
  for (const item of items) {
    console.log(item.name);
  }
});
Incoming deltas are validated against the schema at runtime via Schema.decodeUnknownSync. Invalid entries are discarded.

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API

MethodDescription
add(value: T)Add an element
remove(value: T)Remove all observed instances of an element
values()Returns current Set<T>
onChange(fn)Subscribe — returns unsubscribe function