Serenji from George James Software (GJS) is an extension for Visual Studio Code (VSCode), allowing you to browse, edit and debug InterSystems ObjectScript code directly in namespaces of InterSystems environments.
A cloud-hosted evaluation environment for Serenji is available here.
Serenji includes an embedded edition of the Deltanji source code management product from GJS. Another VSCode extension integrates Deltanji with VSCode as a source control provider that you can interact with from the Source Control viewlet. You can also access Serenji's embedded Deltanji through its web browser UI.