CacheStorage.has()

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句法
范例
规范
浏览器兼容性
另请参阅
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has() 方法在 CacheStorage interface returns a Promise that resolves to true 若 缓存 object matches the cacheName .

You can access CacheStorage through the global caches 特性。

句法

caches.has(cacheName).then(function(boolean) {
  // true: your cache exists!
});

参数

cacheName: DOMString representing the name of the 缓存 object you are looking for in the CacheStorage .

返回值

a Promise that resolves to true if the cache exists or false 若不。

范例

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.
});

规范

规范	状态	注释
服务工作者 The definition of 'CacheStorage: has' in that specification.	工作草案	初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`has`	Chrome 40	Edge 16	Firefox 44 44 Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No	Opera 27	Safari 11.1	WebView Android 40	Chrome Android 40	Firefox Android 44	Opera Android 27	Safari iOS Yes	Samsung Internet Android 4.0

图例

完整支持
不支持
实验。期望将来行为有所改变。

另请参阅

元数据

最后修改： Mar 24, 2020

服务工作者 API
CacheStorage
方法
1. delete()
2. has()
3. keys()
4. match()
5. open()
Related pages for Service Workers API

在此页

句法

参数

返回值

范例

规范

浏览器兼容性

图例

另请参阅

相关话题