feat(walker): implement restoreWalkerAtNode

Author: P0lip

src/walker/types.ts

@@ -1,4 +1,5 @@
-import type { SchemaNode } from '../nodes';
+import type { RegularNode, SchemaNode } from '../nodes';
+import type { RootNode } from '../nodes/RootNode';
 import type { SchemaFragment } from '../types';
 
 export type WalkerRefResolver = (path: string[] | null, $ref: string) => SchemaFragment;
@@ -16,11 +17,12 @@ export type WalkerItem = {
 export type WalkerSnapshot = {
   readonly fragment: SchemaFragment;
   readonly depth: number;
+  readonly schemaNode: RegularNode | RootNode;
   readonly path: string[];
 };
 
 export type WalkerHookAction = 'filter' | 'stepIn';
 export type WalkerHookHandler = (node: SchemaNode) => boolean;
 
-export type WalkerEvent = 'newNode' | 'enterNode' | 'exitNode';
+export type WalkerEvent = 'newNode' | 'acceptNode' | 'enterNode' | 'exitNode';
 export type WalkerEventHandler = (node: SchemaNode) => void;

src/walker/walk.ts

@@ -45,6 +45,7 @@ export class Walker extends EventEmitter<Dictionary<WalkerEventHandler, WalkerEv
     this.path.splice(0, this.path.length, ...snapshot.path);
     this.depth = snapshot.depth;
     this.fragment = snapshot.fragment;
+    this.schemaNode = snapshot.schemaNode;
 
     yield* this.walk();
   }
@@ -53,6 +54,7 @@ export class Walker extends EventEmitter<Dictionary<WalkerEventHandler, WalkerEv
     return {
       depth: this.depth,
       fragment: this.fragment,
+      schemaNode: this.schemaNode,
       path: this.path.slice(),
     };
   }
@@ -61,6 +63,13 @@ export class Walker extends EventEmitter<Dictionary<WalkerEventHandler, WalkerEv
     this.hooks[action] = handler;
   }
 
+  public restoreWalkerAtNode(node: RegularNode) {
+    this.path.splice(0, this.path.length, ...node.path);
+    this.depth = node.depth;
+    this.fragment = node.fragment;
+    this.schemaNode = node;
+  }
+
   public *walk(): IterableIterator<WalkerItem> {
     const {
       depth: initialDepth,
@@ -93,13 +102,15 @@ export class Walker extends EventEmitter<Dictionary<WalkerEventHandler, WalkerEv
         }
       }
 
-      if (!(schemaNode instanceof RegularNode)) continue;
+      super.emit('acceptNode', schemaNode);
 
-      this.schemaNode = schemaNode;
+      if (schemaNode instanceof RegularNode) {
+        this.schemaNode = schemaNode;
 
-      if (this.hooks.stepIn?.(schemaNode) === false) {
-        super.emit('enterNode', schemaNode);
-        yield* this.walkNodeChildren();
+        if (this.hooks.stepIn?.(schemaNode) !== false) {
+          super.emit('enterNode', schemaNode);
+          yield* this.walkNodeChildren();
+        }
       }
 
       super.emit('exitNode', schemaNode);