Feature: New command - Delete Duplicate Lines

src/vs/editor/contrib/linesOperations/linesOperations.ts

@@ -282,6 +282,74 @@ export class SortLinesDescendingAction extends AbstractSortLinesAction {
 	}
 }
 
+export class DeleteDuplicateLinesAction extends EditorAction {
+	constructor() {
+		super({
+			id: 'editor.action.removeDuplicateLines',
+			label: nls.localize('lines.deleteDuplicates', "Delete Duplicate Lines"),
+			alias: 'Delete Duplicate Lines',
+			precondition: EditorContextKeys.writable
+		});
+	}
+
+	public run(_accessor: ServicesAccessor, editor: ICodeEditor): void {
+		if (!editor.hasModel()) {
+			return;
+		}
+
+		let model: ITextModel = editor.getModel();
+		if (model.getLineCount() === 1 && model.getLineMaxColumn(1) === 1) {
+			return;
+		}
+
+		let edits: IIdentifiedSingleEditOperation[] = [];
+		let endCursorState: Selection[] = [];
+
+		let linesDeleted = 0;
+
+		for (let selection of editor.getSelections()) {
+			let uniqueLines = new Set();
+			let lines = [];
+
+			for (let i = selection.startLineNumber; i <= selection.endLineNumber; i++) {
+				let line = model.getLineContent(i);
+
+				if (uniqueLines.has(line)) {
+					continue;
+				}
+
+				lines.push(line);
+				uniqueLines.add(line);
+			}
+
+
+			let selectionToReplace = new Selection(
+				selection.startLineNumber,
+				1,
+				selection.endLineNumber,
+				model.getLineMaxColumn(selection.endLineNumber)
+			);
+
+			let adjustedSelectionStart = selection.startLineNumber - linesDeleted;
+			let finalSelection = new Selection(
+				adjustedSelectionStart,
+				1,
+				adjustedSelectionStart + lines.length - 1,
+				lines[lines.length - 1].length
+			);
+
+			edits.push(EditOperation.replace(selectionToReplace, lines.join('\n')));
+			endCursorState.push(finalSelection);
+
+			linesDeleted += (selection.endLineNumber - selection.startLineNumber + 1) - lines.length;
+		}
+
+		editor.pushUndoStop();
+		editor.executeEdits(this.id, edits, endCursorState);
+		editor.pushUndoStop();
+	}
+}
+
 export class TrimTrailingWhitespaceAction extends EditorAction {
 
 	public static readonly ID = 'editor.action.trimTrailingWhitespace';
@@ -1111,6 +1179,7 @@ registerEditorAction(MoveLinesUpAction);
 registerEditorAction(MoveLinesDownAction);
 registerEditorAction(SortLinesAscendingAction);
 registerEditorAction(SortLinesDescendingAction);
+registerEditorAction(DeleteDuplicateLinesAction);
 registerEditorAction(TrimTrailingWhitespaceAction);
 registerEditorAction(DeleteLinesAction);
 registerEditorAction(IndentLinesAction);

src/vs/editor/contrib/linesOperations/test/linesOperations.test.ts

@@ -11,7 +11,7 @@ import { Selection } from 'vs/editor/common/core/selection';
 import { Handler } from 'vs/editor/common/editorCommon';
 import { ITextModel } from 'vs/editor/common/model';
 import { ViewModel } from 'vs/editor/common/viewModel/viewModelImpl';
-import { DeleteAllLeftAction, DeleteAllRightAction, DeleteLinesAction, IndentLinesAction, InsertLineAfterAction, InsertLineBeforeAction, JoinLinesAction, LowerCaseAction, SnakeCaseAction, SortLinesAscendingAction, SortLinesDescendingAction, TitleCaseAction, TransposeAction, UpperCaseAction } from 'vs/editor/contrib/linesOperations/linesOperations';
+import { DeleteAllLeftAction, DeleteAllRightAction, DeleteDuplicateLinesAction, DeleteLinesAction, IndentLinesAction, InsertLineAfterAction, InsertLineBeforeAction, JoinLinesAction, LowerCaseAction, SnakeCaseAction, SortLinesAscendingAction, SortLinesDescendingAction, TitleCaseAction, TransposeAction, UpperCaseAction } from 'vs/editor/contrib/linesOperations/linesOperations';
 import { withTestCodeEditor } from 'vs/editor/test/browser/testCodeEditor';
 import { createTextModel } from 'vs/editor/test/common/editorTestUtils';
 
@@ -143,6 +143,67 @@ suite('Editor Contrib - Line Operations', () => {
 		});
 	});
 
+	suite('DeleteDuplicateLinesAction', () => {
+		test('should remove duplicate lines', function () {
+			withTestCodeEditor(
+				[
+					'alpha',
+					'beta',
+					'beta',
+					'beta',
+					'alpha',
+					'omicron',
+				], {}, (editor) => {
+					let model = editor.getModel()!;
+					let deleteDuplicateLinesAction = new DeleteDuplicateLinesAction();
+
+					editor.setSelection(new Selection(1, 3, 6, 4));
+					executeAction(deleteDuplicateLinesAction, editor);
+					assert.deepStrictEqual(model.getLinesContent(), [
+						'alpha',
+						'beta',
+						'omicron',
+					]);
+					assertSelection(editor, new Selection(1, 1, 3, 7));
+				});
+		});
+
+		test('should remove duplicate lines in multiple selections', function () {
+			withTestCodeEditor(
+				[
+					'alpha',
+					'beta',
+					'beta',
+					'omicron',
+					'',
+					'alpha',
+					'alpha',
+					'beta'
+				], {}, (editor) => {
+					let model = editor.getModel()!;
+					let deleteDuplicateLinesAction = new DeleteDuplicateLinesAction();
+
+					editor.setSelections([new Selection(1, 2, 4, 3), new Selection(6, 2, 8, 3)]);
+					executeAction(deleteDuplicateLinesAction, editor);
+					assert.deepStrictEqual(model.getLinesContent(), [
+						'alpha',
+						'beta',
+						'omicron',
+						'',
+						'alpha',
+						'beta'
+					]);
+					let expectedSelections = [
+						new Selection(1, 1, 3, 7),
+						new Selection(5, 1, 6, 4)
+					];
+					editor.getSelections()!.forEach((actualSelection, index) => {
+						assert.deepStrictEqual(actualSelection.toString(), expectedSelections[index].toString());
+					});
+				});
+		});
+	});
+
 
 	suite('DeleteAllLeftAction', () => {
 		test('should delete to the left of the cursor', function () {