JS/TS add/remove event listener with a local function saved in a instance var which uses

jsts-event-listener-solution.ts

class Solution extends TestSetting {

  private clickEventHandler:any;

  public addEventListener() {
    this.removeEventListener();

    if (this.element == null) {
      return;
    }

    var that = this;
    this.clickEventHandler = function(event: Event) {
      // 'this' is not the class instance but that is
      console.log(that);
    }
    this.element.addEventListener("click", this.clickEventHandler);
  }

  public removeEventListener() {
    if (this.element == null) {
      return;
    }

    // does remove the listener
    this.element.removeEventListener("click", this.clickEventHandler);
  }
}

const solution = new Solution();
solution.addEventListener();
solution.addEventListener();
solution.simulateOnClick();