IDBRequest.source - Web APIs 编辑

The source read-only property of the IDBRequest interface returns the source of the request, such as an Index or an object store. If no source exists (such as when calling indexedDB.open), it returns null.

Note:

Syntax

var IDBIndex = request.source;
var IDBCursor = request.source;
var IDBObjectStore = request.source;

Value

An object representing the source of the request, such as an IDBIndex, IDBObjectStore or IDBCursor.

Example

The following example requests a given record title, onsuccess gets the associated record from the IDBObjectStore (made available as objectStoreTitleRequest.result), updates one property of the record, and then puts the updated record back into the object store in another request. The source of the 2nd request is logged to the developer console. For a full working example, see our To-do Notifications app (view example live.)

var title = "Walk dog";

// Open up a transaction as usual
var objectStore = db.transaction(['toDoList'], "readwrite").objectStore('toDoList');

// Get the to-do list object that has this title as its title
var objectStoreTitleRequest = objectStore.get(title);

objectStoreTitleRequest.onsuccess = function() {
  // Grab the data object returned as the result
  var data = objectStoreTitleRequest.result;

  // Update the notified value in the object to "yes"
  data.notified = "yes";

  // Create another request that inserts the item
  // back into the database
  var updateTitleRequest = objectStore.put(data);

  // Log the source of this request
  console.log("The source of this request is " + updateTitlerequest.source);
  // When this new request succeeds, run the displayData()
  // function again to update the display
  updateTitleRequest.onsuccess = function() { displayData(); };
};

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.)