imp(UndoRedoManager): stacks transformation logic improved

Author: e11sy

packages/collaboration-manager/src/OperationsTransformer.ts

@@ -120,14 +120,12 @@ export class OperationsTransformer {
        * Cover case 2
        */
       case OperationType.Delete:
-        if (operation.index.blockIndex !== undefined) {
-          if (againstOp.index.blockIndex! < operation.index.blockIndex!) {
-            newIndexBuilder.addBlockIndex(operation.index.blockIndex! - 1);
-          } else {
-            return new Operation(OperationType.Neutral, newIndexBuilder.build(), { payload: [] }, operation.userId, operation.rev);
-          }
+        if (againstOp.index.blockIndex! >= operation.index.blockIndex!) {
+          return new Operation(OperationType.Neutral, newIndexBuilder.build(), { payload: [] }, operation.userId, operation.rev);
         }
 
+        newIndexBuilder.addBlockIndex(operation.index.blockIndex! - 1);
+
         break;
 
       /**
@@ -301,9 +299,7 @@ export class OperationsTransformer {
        * Cover case 2.2
        */
       case (RangeIntersectionType.Right):
-        const overlapLength = index.textRange![1] - againstIndex.textRange![0];
-
-        newIndexBuilder.addTextRange([index.textRange![0], index.textRange![1] - overlapLength]);
+        newIndexBuilder.addTextRange([index.textRange![0], againstIndex.textRange![0]]);
         break;
 
       /**

packages/collaboration-manager/src/UndoRedoManager.ts

@@ -14,6 +14,17 @@ export class UndoRedoManager {
    */
   #redoStack: Operation[] = [];
 
+  /**
+   * Transforms passed operations stack against the operation
+   *
+   * @param operation - operation to transform against
+   * @param stack - stack to transform
+   * @returns - new transformed list of operations
+   */
+  private transformStack(operation: Operation, stack: Operation[]): Operation[] {
+    return stack.map((op: Operation) => op.transform(operation));
+  }
+
   /**
    * Returns operation to undo (if any)
    */
@@ -65,28 +76,7 @@ export class UndoRedoManager {
    * @param operation - operation to transform against
    */
   public transformStacks(operation: Operation): void {
-    this.transformStack(operation, this.#undoStack);
-    this.transformStack(operation, this.#redoStack);
-  }
-
-  /**
-   * Transforms passed operations stack against the operation
-   *
-   * @param operation - operation to transform against
-   * @param stack - stack to transform
-   */
-  public transformStack(operation: Operation, stack: Operation[]): void {
-    const transformed = stack.flatMap((op) => {
-      const transformedOp = op.transform(operation);
-
-      if (transformedOp === null) {
-        return [];
-      }
-
-      return [ transformedOp ];
-    });
-
-    stack.length = 0;
-    stack.push(...transformed);
+    this.#undoStack = this.transformStack(operation, this.#undoStack);
+    this.#redoStack = this.transformStack(operation, this.#redoStack);
   }
 }