Observer #

Available since 7.8.0

The Observer class allows to manipulate realtime documents. A RealtimeDocument is like a normal document from Kuzzle except that it is connected to the realtime engine and it's content will change with changes occuring on the database.

They can be retrieved using methods with the same syntax as in the Document Controller:

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const docs = await observer.get('nyc-open-data', 'yellow-taxi', 'foobar');

const result = await observer.search('nyc-open-data', 'yellow-taxi', {
  query: { exists: 'licence' }
});

Realtime documents are resources that should be disposed via the Observer.stop method otherwise subscriptions will never be terminated, documents will be kept into memory, which might lead to a memory leak.

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await observer.stop('nyc-open-data', 'yellow-taxi');

A good frontend practice is to instantiate one observer for the actual page and/or component(s) displaying realtime documents and to dispose them when they are not displayed anymore.

Using HTTP protocol #

Available since 7.8.3

If the SDK is using the HTTP protocol, then documents are retrieved through the document.mGet method every specified interval (default is 5 sec).

This interval can be modified with the pullingDelay option of the constructor.