@Observable

Reactive properties — subscribe to changes on instance fields and derived getters.

Kind	Runtime
Backends	legacy, stage3
Requires generate	No

Example

import { Observable } from 'lombok-typescript/legacy';

@Observable
class Counter {
  count = 0;
}

const c = new Counter();
c.subscribe('count', (next, prev) => console.log(next, prev));
c.count = 1;

c.subscribe('*', (key, next, prev) => console.log(key, next, prev));

Derived getters

@Observable
class Cart {
  items: number[] = [];

  @Observable.Derived
  get total() {
    return this.items.reduce((s, n) => s + n, 0);
  }
}

@Observer is an alias for @Observable (GoF naming).

Adapters

• RxJS / MobX adapters

Caveats

• Instances are wrapped in a Proxy; instanceof checks against the undecorated class may fail.
• Assign properties on the instance returned from new so the proxy set trap fires.