IDBCursor.source - Web APIs 编辑

The source read-only property of the IDBCursor interface returns the IDBObjectStore or IDBIndex that the cursor is iterating over. This function never returns null or throws an exception, even if the cursor is currently being iterated, has iterated past its end, or its transaction is not active.

Note:

Syntax

var source = cursor.source;

Value

The IDBObjectStore or IDBIndex that the cursor is iterating over.

Example

In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store. Within each iteration we log the source of the cursor, which will log our IDBobjectStore object to the console, something like this:

IDBObjectStore {autoIncrement: false, transaction: IDBTransaction, indexNames: DOMStringList, keyPath: "albumTitle", name: "rushAlbumList"…}

The cursor does not require us to select the data based on a key; we can just grab all of it. Also note that in each iteration of the loop, you can grab data from the current record under the cursor object using cursor.value.foo. For a complete working example, see our IDBCursor example (view example live.)

function displayData() {
  var transaction = db.transaction(['rushAlbumList'], "readonly");
  var objectStore = transaction.objectStore('rushAlbumList');

  objectStore.openCursor().onsuccess = function(event) {
    var cursor = event.target.result;
    if(cursor) {
      var listItem = document.createElement('li');
      listItem.innerHTML = cursor.value.albumTitle + ', ' + cursor.value.year;
      list.appendChild(listItem);

      console.log(cursor.source);
      cursor.continue();
    } else {
      console.log('Entries all displayed.');
    }
  };
};

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using IndexedDB
• Starting transactions: IDBDatabase
• Using transactions: IDBTransaction
• Setting a range of keys: IDBKeyRange
• Retrieving and making changes to your data: IDBObjectStore
• Using cursors: IDBCursor
• Reference example: To-do Notifications (view example live.)