bed3f7f69a
We have no way of detecting if a browser window is behind another window or off screen on a virtual desktop. In some cases we may want events to be delivered quicker to the browser. Specifically a user may still have a window in view but is not interacting. This gives users 20 minutes of extra "long polling time" prior to shifting to short polling.
47 lines
1.3 KiB
JavaScript
47 lines
1.3 KiB
JavaScript
// for android we test webkit
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const hiddenProperty =
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document.hidden !== undefined
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? "hidden"
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: document.webkitHidden !== undefined
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? "webkitHidden"
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: undefined;
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const MAX_UNSEEN_TIME = 60000;
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let seenUserTime = Date.now();
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export default function(maxUnseenTime) {
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maxUnseenTime = maxUnseenTime === undefined ? MAX_UNSEEN_TIME : maxUnseenTime;
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const now = Date.now();
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if (seenUserTime + maxUnseenTime < now) {
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return false;
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}
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if (hiddenProperty !== undefined) {
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return !document[hiddenProperty];
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} else {
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return document && document.hasFocus;
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}
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}
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export function seenUser() {
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seenUserTime = Date.now();
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}
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// We could piggieback on the Scroll mixin, but it is not applied
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// consistently to all pages
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//
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// We try to keep this as cheap as possible by performing absolute minimal
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// amount of work when the event handler is fired
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//
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// An alternative would be to use a timer that looks at the scroll position
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// however this will not work as message bus can issue page updates and scroll
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// page around when user is not present
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//
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// We avoid tracking mouse move which would be very expensive
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$(document).bind("touchmove.discourse-track-presence", seenUser);
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$(document).bind("click.discourse-track-presence", seenUser);
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$(window).bind("scroll.discourse-track-presence", seenUser);
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