There is an update of the API of event listeners.
In short this:
document.addEventListener('touchstart', handler, true);
becomes this:
document.addEventListener('touchstart', handler, {capture: true});
Since in your case you attach event listener to touchstart it should be like that:
document.addEventListener('touchstart', handler, {passive: true});
This way you can setup in advance which exact event and if the passive interface is supported:
var passiveEvent = false;
try {
var opts = Object.defineProperty({}, 'passive', {
get: function () {
passiveEvent = true;
}
});
window.addEventListener("test", null, opts);
} catch (e) { }
// in my case I need both passive and capture set to true, change as you need it.
passiveEvent = passiveEvent ? { capture: true, passive: true } : true;
//if you need to handle mouse wheel scroll
var supportedWheelEvent: string = "onwheel" in HTMLDivElement.prototype ? "wheel" :
document.onmousewheel !== undefined ? "mousewheel" : "DOMMouseScroll";
And use like this:
elementRef.addEventListener("touchstart", handler, passiveEvent);
More details on passive event listeners here:
https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md
