Support for VSCode Command workbench.action.revertAndCloseActiveEditor

[nmorenor]

We have an extension and we are looking to be compatible with Theia IDE I see that there are already work in progress to support the vscode built-in commands at 4050. Which will make the extension to work as if it were running on vscode.

We are using also the command workbench.action.revertAndCloseActiveEditor. I've just cloned the Theia repo and manually and dropped the .vsix under plugins directory.

[akosyakov]

Missing editor commands should be added here: https://github.com/eclipse-theia/theia/blob/master/packages/plugin-ext-vscode/src/browser/plugin-vscode-commands-contribution.ts#L348

Referenced implementation in VS Code: https://github.com/microsoft/vscode/blob/3f0e5b4ab059cb6c05ecac091b652cfc50b9292f/src/vs/workbench/browser/parts/editor/editorActions.ts#L462

In Theia:

• to revert: MonacoEditor.getCurrent(EditorManager).document.revert
• to close: EditorManager.close(EditorManager.current.id)

Don't forget to await.