grid - 💄 for viewcolumn conversion

src/vs/workbench/api/shared/editor.ts

@@ -5,7 +5,31 @@
 
 'use strict';
 
+import { IEditorGroupsService } from 'vs/workbench/services/group/common/editorGroupsService';
+import { GroupIdentifier } from 'vs/workbench/common/editor';
+import { ACTIVE_GROUP, SIDE_GROUP } from 'vs/workbench/services/editor/common/editorService';
+
 // TODO@api this was previously a hardcoded list of editor positions (ONE, TWO, THREE)
 // that with the introduction of grid editor feature is now unbounded. This should be
 // revisited when the grid functionality is exposed to extensions
-export type EditorPosition = number;
+export type EditorViewColumn = number;
+
+export function viewColumnToEditorGroup(editorGroupService: IEditorGroupsService, position?: EditorViewColumn): GroupIdentifier {
+	if (typeof position !== 'number') {
+		return ACTIVE_GROUP; // prefer active group when position is undefined
+	}
+
+	const groups = editorGroupService.groups;
+
+	let candidate = groups[position];
+	if (candidate) {
+		return candidate.id; // found direct match
+	}
+
+	let firstGroup = groups[0];
+	if (groups.length === 1 && firstGroup.count === 0) {
+		return firstGroup.id; // first editor should always open in first group
+	}
+
+	return SIDE_GROUP; // open to the side if group not found
+}