import {
  DisposableCollection,
  EventEmitter,
  IDisposable
} from "@stoplight/lifecycle";

export class Editor implements IDisposable {
  // EventEmitter itself is an IDisposable
  public readonly valueEmitter = new EventEmitter<string, "didUpdate">();

  private readonly disposables: DisposableCollection = new DisposableCollection();

  constructor() {
    this.disposables.push(this.valueEmitter);
  }

  // Implement IDisposable
  dispose() {
    this.disposables.dispose();
  }
}

import { EventEmitter, IDisposable } from "@stoplight/lifecycle";

class Editor implements IDisposable {
  private _value = "";

  // create an emitter instance for this editor, defining the possible events and event object value
  private valueEmitter = new EventEmitter<string, "willUpdate" | "didUpdate">();

  get value() {
    return this._value;
  }

  set value(val: string) {
    this.valueEmitter.emit("willUpdate", this._value);
    this._value = val;
    this.valueEmitter.emit("didUpdate", this._value);
  }

  get onWillUpdateValue() {
    return this.valueEmitter.on("willUpdate");
  }

  get onDidUpdateValue() {
    return this.valueEmitter.on("didUpdate");
  }

  dispose() {
    // best practice to cleanup the emitter
    this.valueEmitter.dispose();
  }
}

const editor = new Editor();

const willUpdateListener = editor.onWillUpdateValue(val => {
  console.log("next value: ", val);
});

const didUpdateListener = editor.onDidUpdateValue(val => {
  console.log("new value: ", val);
});

// stop listening to willUpdate event
willUpdateListener.dispose();