Straight to your questions:
- The approach is correct. For the updated items, you should also check if they are not new. New items could also be changed and become dirty.
- isNew will return false if you set the id field value to be different then the default one.
- Yes, you can set the data option and use the dataSource as local storage. You might also consider using a dataSource with custom functions for the transport operations(examples are available in the documentation). This way the created, deleted and updated items will be passed to the corresponding function and you will not need to filter the items manually.
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