javascript - 警告 : Added non-passive event listener to a scroll-blocking 'touchstart' event

Question

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Answer 1

事件监听器API有更新。

简而言之:

document.addEventListener('touchstart', handler, true);

变成这样:

document.addEventListener('touchstart', handler, {capture: true});

因为在你的情况下你将事件监听器附加到 touchstart 它应该是这样的:

document.addEventListener('touchstart', handler, {passive: true});

通过这种方式，您可以提前设置确切的事件以及是否支持被动接口(interface):

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";

然后像这样使用:

elementRef.addEventListener("touchstart", handler, passiveEvent);

有关被动事件监听器的更多详细信息，请参见此处: https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md