function NavigationHelpButtonViewModel() {
  /**
   * Gets or sets whether the instructions are currently shown.  This property is observable.
   * @type {boolean}
   * @default false
   */
  this.showInstructions = false;

  const that = this;
  this._command = createCommand(function () {
    that.showInstructions = !that.showInstructions;
  });
  this._showClick = createCommand(function () {
    that._touch = false;
  });
  this._showTouch = createCommand(function () {
    that._touch = true;
  });

  this._touch = false;

  /**
   * Gets or sets the tooltip.  This property is observable.
   *
   * @type {string}
   */
  this.tooltip = "Navigation Instructions";

  knockout.track(this, ["tooltip", "showInstructions", "_touch"]);
}
The view model for {@link NavigationHelpButton}.
@alias NavigationHelpButtonViewModel
@constructor