Method subscribe

src/state/Property.js:48–50

* Adds a subscriber to this property. * @param {function} callback The callback to call whenever the property changes.

(callback)

   * @param {function} callback The callback to call whenever the property changes.
   */
  subscribe(callback) {
    this.listeners.push(callback);
  }

  /**
   * Unsubscribes a listener from this property.