| name | source-operation-capabilities |
| description | Understand how sources declare operation capabilities via supportedOperations and how SourceList respects them. |
| metadata | {"last_modified":"Wed, 22 Jul 2026 15:00:00 GMT"} |
In pkg:data_layer, DataContract and Source declare supported operation types via the supportedOperations getter, which returns a Set<SourceOperationType>.
By default, DataContract supports standard CRUD operations (getById, getByIds, getItems, setItem, setItems, delete).
Specific mixins add additional supported operations:
WatchableSource: Adds watch, watchList, and watchByIds.MessageWriteMixin: Adds sendMessage.
ProxySource populates supportedOperations dynamically based on which handler callbacks were passed to its constructor.
// Check if a source supports a given operation type
if (source.supports(operation.type)) {
await source.setItem(operation);
}
The SourceList automatically checks source.supports(operation.type) before invoking operations on each source, skipping sources that do not support the operation without throwing UnimplementedError.
