Resolve conflicts using files from Stirling-2.0

stirling-pdf/build/resources/main/static/js/multitool/UndoManager.js

@@ -0,0 +1,65 @@
+export class UndoManager {
+  _undoStack;
+  _redoStack;
+
+  constructor() {
+    this._undoStack = [];
+    this._redoStack = [];
+  }
+
+  pushUndo(command) {
+    this._undoStack.push(command);
+    this._dispatchStateChange();
+  }
+
+  pushRedo(command) {
+    this._redoStack.push(command);
+    this._dispatchStateChange();
+  }
+
+  pushUndoClearRedo(command) {
+    this._undoStack.push(command);
+    this._redoStack = [];
+    this._dispatchStateChange();
+  }
+
+  undo() {
+    if (!this.canUndo()) return;
+
+    let cmd = this._undoStack.pop();
+    cmd.undo();
+
+    this._redoStack.push(cmd);
+    this._dispatchStateChange();
+  }
+
+  canUndo() {
+    return this._undoStack && this._undoStack.length > 0;
+  }
+
+  redo() {
+    if (!this.canRedo()) return;
+
+    let cmd = this._redoStack.pop();
+    cmd.redo();
+
+    this._undoStack.push(cmd);
+    this._dispatchStateChange();
+  }
+
+  canRedo() {
+    return this._redoStack && this._redoStack.length > 0;
+  }
+
+  _dispatchStateChange() {
+    document.dispatchEvent(
+      new CustomEvent("undo-manager-update", {
+        bubbles: true,
+        detail: {
+          canUndo: this.canUndo(),
+          canRedo: this.canRedo(),
+        },
+      })
+    );
+  }
+}