How to use the atom.Emitter function in atom

constructor(options) {
      this.element = document.createElement('select');
      this.element.classList.add('select', 'element');
      this.element.style.width = options.width;

      this.emitter = new Emitter();
      this.element.onchange = function(e){
          var selectedOption = this.element.options[this.element.selectedIndex];
          this.emitter.emit('change', {text: selectedOption.text, value: selectedOption.value});
      }.bind(this);
    }

constructor (gitStore: GitStore) {
    this.emitter = new Emitter()
    this.gitStore = gitStore
  }

constructor(delay) {
    this.events = []
    this.ranEvents = []
    this.delay = delay
    this.isRunning = false
    this.emitter = new Emitter()
  }

constructor(data) {
        this.data = data;
        this.itemElement = document.createElement('div');
        this.itemElement.className = 'layer-gutter-item';
        this.itemElement.style['width'] = '100%';
        this.contentElement = document.createElement('div');
        this.itemElement.appendChild(this.contentElement);
        const resizeHandle = new GutterResizeHandle();
        this.resizeEmitter = resizeHandle.emitter;
        this.itemElement.appendChild(resizeHandle.element());
        this.emitter = new Emitter();
        this.boundMouseEnterListener = this.mouseEnterListener.bind(this);
        this.boundMouseLeaveListener = this.mouseLeaveListener.bind(this);
        this.itemElement.addEventListener('mouseenter', this.boundMouseEnterListener);
    }
    setIndicator(value) {

constructor() {
        this.handleElement = document.createElement('div');
        this.handleElement.className = 'layer-resize-handle';
        this.emitter = new Emitter();
        this.boundMouseDownListener = this.mouseDownListener.bind(this);
        this.boundMouseUpListener = this.mouseUpListener.bind(this);
        this.boundMouseMoveListener = this.mouseMoveListener.bind(this);
        this.handleElement.addEventListener('mousedown', this.boundMouseDownListener);
    }
    mouseDownListener(event) {