zulip/static/js/watchdog.js

35 lines
1.0 KiB
JavaScript

const unsuspend_callbacks = [];
let watchdog_time = Date.now();
/*
Our watchdog code checks every 5 seconds to make sure that we
haven't gone 20 seconds since the last "5-second-ago" check.
This sounds confusing, but it is just is a way to detect that
the machine has gone to sleep.
When we detect the condition we call back to server_events code
to reset ourselves accordingly.
*/
export function check_for_unsuspend() {
const new_time = Date.now();
if (new_time - watchdog_time > 20000) {
// 20 seconds.
// Defensively reset watchdog_time here in case there's an
// exception in one of the event handlers
watchdog_time = new_time;
// Our app's JS wasn't running, which probably means the machine was
// asleep.
for (const callback of unsuspend_callbacks) {
callback();
}
}
watchdog_time = new_time;
}
export function on_unsuspend(f) {
unsuspend_callbacks.push(f);
}
setInterval(check_for_unsuspend, 5000);