feat: walk json model can delete nodes

Signed-off-by: Christian Stewart <christian@aperture.us>

Author: paralin

src/model/walk.ts

@@ -1,7 +1,24 @@
 import { IJsonModel, IJsonBorderNode, IJsonRowNode, IJsonTabSetNode, IJsonTabNode } from "./IJsonModel";
 
+/** Union type representing all possible node types in the JSON model */
 export type JsonNode = IJsonBorderNode | IJsonRowNode | IJsonTabSetNode | IJsonTabNode;
-export type ModelVisitor = (node: JsonNode, parent: JsonNode | null) => boolean | void;
+export interface VisitorResult {
+    /** If true, do not process any children of the current node */
+    skipChildren?: boolean;
+    /** If true, remove the current node from its parent's children array */
+    delete?: boolean;
+}
+
+/**
+ * Function type for visiting nodes in the model tree
+ * @param node The current node being visited
+ * @param parent The parent of the current node, or null for top-level nodes
+ * @returns 
+ * - void/true to continue normally
+ * - false to stop traversal completely
+ * - VisitorResult to control traversal or delete nodes
+ */
+export type ModelVisitor = (node: JsonNode, parent: JsonNode | null) => void | boolean | VisitorResult;
 
 /**
  * Finds a node by its ID in the model tree
@@ -15,9 +32,9 @@ export function findJsonNodeById(model: IJsonModel, id: string): JsonNode | unde
     walkJsonModel(model, (node) => {
         if ("id" in node && node.id === id) {
             result = node;
-            return false; // stop walking
+            return { skipChildren: true }; // found it, no need to check children
         }
-        return true;
+        return true
     });
 
     return result;
@@ -27,7 +44,11 @@ export function findJsonNodeById(model: IJsonModel, id: string): JsonNode | unde
  * Walks an IJsonModel tree using a stack-based approach, calling visitor for each node.
  * The walk processes borders first, then traverses the main layout in a depth-first manner.
  * @param model The model to traverse
- * @param visitor Callback called for each node in the tree. Return false to stop the traversal.
+ * @param visitor Callback called for each node in the tree. The visitor can:
+ *               - Return false to stop the traversal completely
+ *               - Return {skipChildren: true} to skip processing children
+ *               - Return {delete: true} to remove the current node from its parent
+ *               - Return nothing or true to continue normally
  *               The visitor receives the current node and its parent (null for top-level nodes).
  */
 export function walkJsonModel(model: IJsonModel, visitor: ModelVisitor): void {
@@ -48,13 +69,28 @@ export function walkJsonModel(model: IJsonModel, visitor: ModelVisitor): void {
     while (stack.length > 0) {
         const [node, parent] = stack.pop()!;
 
-        // Visit current node, stop if visitor returns false
-        if (visitor(node, parent) === false) {
+        // Visit current node
+        const result = visitor(node, parent);
+        
+        // Handle different return types
+        if (result === false) {
             break;
         }
 
-        // Add children to stack in reverse order so they're processed in forward order
-        if ("children" in node) {
+        const visitorResult = typeof result === 'object' ? result : undefined;
+        
+        // Handle deletion if requested
+        if (visitorResult?.delete && parent && "children" in parent) {
+            const index = parent.children.findIndex(child => child === node);
+            if (index !== -1) {
+                parent.children.splice(index, 1);
+                continue;
+            }
+        }
+
+        // Skip children if requested or process them
+        if (!visitorResult?.skipChildren && "children" in node) {
+            // Add children to stack in reverse order so they're processed in forward order
             for (let i = node.children.length - 1; i >= 0; i--) {
                 stack.push([node.children[i], node]);
             }