handle escape function (working TypeScript code included)

i'd like to get a callback when escape function is called. I'll provide my implementation bellow:

1) I'm using it as fowollows <modal showing.bind="showing" escape-callback.call="escapeCallback()">

2) i changed modal.js so that it

accepts bindable escapeCallback
registers a keyboard handler when modal is shown ((attached and showing) or state changes to showing = true):
unregisters keyboard handler when modal is hidden or detached

My implementation is following (My source is in TypeScript instead of ES6 that is used in this project - but it is quite strait-forward to port it back to ES6):

import {inject, customElement, bindable} from 'aurelia-framework';
import * as $ from 'jquery';

@customElement('modal')
@inject(Element)
export class Modal {
  @bindable showing = false;
  @bindable escapeCallback: () => void;
  private keydownHandler;
  private modal: Element;
  constructor(private element: Element) {
  }

  attached(){
    $(this.modal).modal({show: false});
    if(this.showing) {
      this.addEscHandler();
    }
  }

  detached() {
    this.removeEscHandler();
  }

  showingChanged(newValue){
    if (newValue) {
      this.addEscHandler();
      $(this.modal).modal('show')
    } else {
      $(this.modal).modal('hide')
      this.removeEscHandler();
    }
  }

  addEscHandler() {
    if(this.escapeCallback && !this.keydownHandler) {
      this.keydownHandler = (e: JQueryEventObject) => {
        if(e.which == 27) { // escape was pressed
          this.escapeCallback();
        }
      };
      $(this.modal).on("keydown.dismiss.bs.modal", this.keydownHandler);
    }
  }

  removeEscHandler() {
    if(this.keydownHandler) {
      $(this.modal).off("keydown.dismiss.bs.modal", this.escapeCallback);
      this.keydownHandler = null;
    }
  }
}

plwalters / aurelia-bs-modal

handle escape function (working TypeScript code included) #16