此代码正在加载DOM内容时注册滚动事件侦听器。卸载组件时,我正在调用removeEventListener()
方法,但是事件侦听器未删除,而是在其他组件中调用。我要去哪里错了?谢谢!
useEffect(() => {
return () => {
document.removeEventListener('scroll', listener, true);
console.log('unmount');
};
}, []);
useLayoutEffect(() => {
document.addEventListener('DOMContentLoaded', (event) => {
document.addEventListener('scroll', listener, true);
});
});
const listener = () => {
let elementTop = $('.foo').offset().top;
let elementBottom = elementTop + $('.foo').outerHeight();
let viewportTop = $(window).scrollTop();
let viewportBottom = viewportTop + $(window).height();
let boolean = elementBottom > viewportTop && elementTop < viewportBottom;
boolean ? setMapAbsolute(true) : setMapAbsolute(false);
};
检查DOMContentLoaded
被触发了多少次,也为页面上的iframes
调用了它。您可能正在为框架注册事件处理程序,但仅将其删除一次。