CacheStorage.has() - Web APIs 编辑
The has()
method of the CacheStorage
interface returns a Promise
that resolves to true
if a Cache
object matches the cacheName
.
You can access CacheStorage
through the global caches
property.
Syntax
caches.has(cacheName).then(function(boolean) { // true: your cache exists! });
Parameters
cacheName
- A
DOMString
representing the name of theCache
object you are looking for in theCacheStorage
.
Return value
a Promise
that resolves to true
if the cache exists or false
if not.
Examples
The following example first checks whether a cache called 'v1' exists. If so, we add a list of assets to it. If not then we run some kind of cache set-up function.
caches.has('v1').then(function(hasCache) {
if (!hasCache) {
someCacheSetupfunction();
} else {
caches.open('v1').then(function(cache) {
return cache.addAll(myAssets);
});
}
}).catch(function() {
// Handle exception here.
});
Specifications
Specification | Status | Comment |
---|---|---|
Service Workers The definition of 'CacheStorage: has' in that specification. | Working Draft | Initial definition. |
Browser compatibility
BCD tables only load in the browser
See also
如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。

绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱,如果其他用户或者作者回复了您的评论,将不能在第一时间通知您!
发布评论