Expose search managed properties and result sources through REST and CSOM.
This will enable developers to build richer property searching applications.
Thanks for your feedback! Although we appreciate your time and effort to give us this feedback, it’s not something we’re planning to do right now. We are targeting our API efforts on the Graph API side and due to internal prioritize are not planning to allocate resources to new CSOM capabilities.
As search is also moving away from the SharePoint to be a service cross Office 365, these APIs are no longer relevant through the SharePoint platform.