didTimeout property on the
IdleDeadline interface is a Boolean value which indicates whether or not the idle callback is being invoked because the timeout interval specified when
Window.requestIdleCallback() was called has expired.
timeRemaining() method will return approximately 0.
Idle callbacks support the concept of a timeout in order to ensure that whatever task they're meant to perform actually happens, even if the user agent never has enough idle time available. Your callback will typically check the value of
didTimeout if it needs to perform an action even if the browser is too busy to grant you the time; you should react by performing the needed task or, ideally, a minimal amount of work that can be done to keep things moving along, then schedule a new callback to try again to get the rest of the work done.
var timedOut = IdleDeadline.didTimeout;
A Boolean which is
true if the callback is running due to the callback's timeout period elapsing or
false if the callback is running because the user agent is idle and is offering time to the callback.
|Cooperative Scheduling of Background Tasks||Working Draft|
|Feature||Chrome||Edge||Firefox (Gecko)||Internet Explorer||Opera||Safari (WebKit)|
|Basic support||47||No support||53 (53)||No support||34||No support|
|Feature||Android||Chrome||Firefox Mobile (Gecko)||Firefox OS||IE Phone||Opera Mobile||Safari Mobile|
|Basic support||53||55||53.0 (53)||?||No support||37||No support|
 Idle callback support was added in Firefox 53, but was disabled by default. To enable it, set the preference
true. Idle callbacks are enabled by default starting in Firefox 55.