Method subscribe

src/db.ts:17–23

(subscriber:IndexSubscriber<T>)

  constructor() {}

  subscribe(subscriber:IndexSubscriber<T>) {
    if(this.subscribers.indexOf(subscriber) === -1) {
      this.subscribers.push(subscriber);
      return true;
    }
    return false;
  }

  unsubscribe(subscriber:IndexSubscriber<T>) {
    let ix = this.subscribers.indexOf(subscriber);