Cache: add() method
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Web Workers.
The add()
method of the Cache
interface takes a URL, retrieves it, and adds the resulting response object to the given cache.
The add()
method is functionally equivalent to the following:
fetch(url).then((response) => {
if (!response.ok) {
throw new TypeError("bad response status");
}
return cache.put(url, response);
});
For more complex operations, you'll need to use Cache.put()
directly.
Note: add()
will overwrite any key/value pair previously stored in the cache that matches the request.
Syntax
add(request)
Parameters
request
-
A request for the resource you want to add to the cache. This can be a
Request
object or a URL.This parameter is used as a parameter to the
Request()
constructor, so URLs follow the same rules as for that constructor. In particular, URLs may be relative to the base URL, which is the document'sbaseURI
in a window context, orWorkerGlobalScope.location
in a worker context.
Return value
A Promise
that resolves with undefined
.
Exceptions
TypeError
-
The URL scheme is not
http
orhttps
.The Response status is not in the 200 range (i.e., not a successful response.) This occurs if the request does not return successfully, but also if the request is a cross-origin no-cors request (in which case the reported status is always 0.)
Examples
This code block waits for an InstallEvent
to fire, then calls waitUntil()
to handle the install process for the app. This consists of calling CacheStorage.open
to create a new cache, then using Cache.add
to add an asset to it.
this.addEventListener("install", (event) => {
event.waitUntil(caches.open("v1").then((cache) => cache.add("/index.html")));
});
Specifications
Specification |
---|
Service Workers # cache-add |
Browser compatibility
BCD tables only load in the browser