Graph API : Planner API, ODATA support, $filter, $top, $orderby...
Enable , ODATA in Planner API's, to permite $filter,$top, $orderby, ...
At this moment ODATA is not support all ODATA, only support $select.
Many users have plans that are very large and supporting these kinds of APIs would result in an unpredictable experience for your users, since queries could be throttled.
The best approach is to use the one taken by our first-party client. Retrieve all the tasks and then filter them client side.
Our APIs are performant, so retrieving tasks and processing them locally should be easy. For large datasets, you can use diff sync to retrieve any updates that have happened on the service and update your local cache.
Phillip Demro commented
I agree with OP that the best approach is using the standard OData protocol which Microsoft is using many other places in the Graph API
Thomas Gorgolione commented
How would one get only incomplete items? Getting all of the tasks assigned would cause a lot of unnecessary downloading (and not ideal for bandwidth limited clients), no?