IDBCursor.continuePrimaryKey()

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continuePrimaryKey() 方法在 IDBCursor interface advances the cursor to the to the item whose key matches the key parameter as well as whose primary key matches the primary key parameter.

A typical use case, is to resume the iteration where a previous cursor has been closed, without having to compare the keys one by one.

Calling this method more than once before new cursor data has been loaded - for example, calling continuePrimaryKey() twice from the same onsuccess handler - results in an InvalidStateError being thrown on the second call because the cursor’s got value flag has been unset.

This method is only valid for cursors coming from an index. Using it for cursors coming from an object store will throw an error.

注意： 此特征可用于 Web 工作者 .

句法

cursor.continuePrimaryKey(key, primaryKey);

参数

key
primaryKey

异常

此方法可能引发 DOMException of one of the following types:

异常	描述
`TransactionInactiveError`	This IDBCursor's transaction is inactive.
`DataError`	The key parameter may have any of the following conditions: The key is not a valid key. The key is less than or equal to this cursor's position and the cursor's direction is `next` or `nextunique` . The key is greater than or equal to this cursor's position and this cursor's direction is `prev` or `prevunique` .
`InvalidStateError`	The cursor is currently being iterated or has iterated past its end.
`InvalidAccessError`	The cursor's direction is not `prev` or `next` .

范例

here’s how you can resume an iteration of all articles tagged with "javascript" since your last visit:

let request = articleStore.index("tag").openCursor();
let count = 0;
let unreadList = [];
request.onsuccess = (event) => {
    let cursor = event.target.result;
    if (!cursor) { return; }
    let lastPrimaryKey = getLastIteratedArticleId();
    if (lastPrimaryKey > cursor.primaryKey) {
      cursor.continuePrimaryKey("javascript", lastPrimaryKey);
      return;
    }
    // update lastIteratedArticleId
    setLastIteratedArticleId(cursor.primaryKey);
    // preload 5 articles into the unread list;
    unreadList.push(cursor.value);
    if (++count < 5) {
      cursor.continue();
    }
};

规范

规范	状态	注释
索引数据库 API 草案 The definition of 'continuePrimaryKey()' in that specification.	推荐

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
`continuePrimaryKey`	Chrome 58	Edge 79	Firefox 51 51 不支持 10 — 51 Prefixed Prefixed Implemented with the vendor prefix: moz	IE ?	Opera 45	Safari 10.1	WebView Android 58	Chrome Android 58	Firefox Android 51	Opera Android 43	Safari iOS 10.3	Samsung Internet Android 7.0

图例

完整支持
兼容性未知 ?
要求使用供应商前缀或不同名称。

另请参阅

使用 IndexedDB
开始事务： IDBDatabase
使用事务： IDBTransaction
设置一系列键： IDBKeyRange
检索并使您的数据改变： IDBObjectStore
使用光标： IDBCursor
参考范例：待办通知 ( 实时查看范例 )。

元数据

最后修改： May 5, 2020

IndexedDB API
IDBCursor
特性
1. direction
2. key
3. primaryKey
4. request
5. source
方法
1. advance()
2. continue()
3. continuePrimaryKey()
4. delete()
5. update()
IndexedDB 相关页面

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句法

参数

异常

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规范

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图例

另请参阅

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