DeferredRequestInit
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The DeferredRequestInit dictionary of the fetchLater() API represents the set of options that can be used to configure a deferred fetch request.
The DeferredRequestInit object is passed directly into the window.fetchLater() function call as the second argument.
Instance properties
This dictionary extends the RequestInit dictionary with the addition of the following properties:
activateAfterOptional-
A
DOMHighResTimeStampindicating a timeout in milliseconds after which the fetch request should be sent. The fetch can be sent earlier on navigating away. The actual sending time is unknown, as the browser may wait for a longer or shorter time, for example, to optimize the batching of deferred fetches. If theactivateAfterproperty is not provided, the deferred fetch waits until the end of the page visit (including entering the bfcache).
Exceptions
RangeErrorDOMException-
Raised when a negative
activateAfteris provided.
Examples
Defer a GET request until the page is destroyed or enters the bfcache
In this example, no DeferredRequestInit object is provided and no timeout is used:
fetchLater("/send_beacon");
Defer a POST request for around 1 minute
In this example we create a Request, and provide an activateAfter value to delay sending the request for 60,000 milliseconds (or one minute):
fetchLater("/send_beacon", {
method: "POST",
body: getBeaconData(),
activateAfter: 60000, // 1 minute
});
Note: The actual sending time is unknown, as the browser may wait for a longer or shorter period of time, for example to optimize batching of deferred fetches.
Specifications
| Specification |
|---|
| Fetch # deferred-fetch |
Browser compatibility
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