refactor(utils): 将 diffNode 实现从递归改为迭代遍历

src/utils/diffEngine.ts

@@ -19,7 +19,6 @@ const buildPath = (parent: string, key: string, isArrayChild: boolean): string =
   }
   const needsEscaping = key.includes('.') || key.includes('[') || key.includes(' ');
   const formattedKey = needsEscaping ? `["${key}"]` : `.${key}`;
-
   return parent === ROOT_PATH ? `${ROOT_PATH}${formattedKey}` : `${parent}${formattedKey}`;
 };
 
@@ -30,104 +29,48 @@ const primitiveEqual = (a: unknown, b: unknown): boolean => {
   return a === b;
 };
 
-const diffNode = (
+// ---------- 迭代遍历框架 ----------
+
+interface StackFrame {
+  left: MaybeMissing;
+  right: MaybeMissing;
+  key: string;
+  path: string;
+  /** 子节点数量（组装时从 resultStack 弹出） */
+  childCount: number;
+  /** 是否已展开 */
+  assembled: boolean;
+  /** 分类结果缓存 */
+  leftObj: boolean;
+  rightObj: boolean;
+  leftArr: boolean;
+  rightArr: boolean;
+  leftIsContainer: boolean;
+  rightIsContainer: boolean;
+}
+
+const createLeafNode = (
+  key: string,
+  path: string,
+  type: DiffNode['type'],
+  oldValue: MaybeMissing,
+  newValue: MaybeMissing,
+): DiffNode => ({
+  key,
+  type,
+  oldValue: oldValue === SENTINEL ? undefined : oldValue,
+  newValue: newValue === SENTINEL ? undefined : newValue,
+  path,
+  isLeaf: true,
+  hasDiffInChildren: false,
+});
+
+const classifyPrimitive = (
   left: MaybeMissing,
   right: MaybeMissing,
   key: string,
   path: string,
-  diffPaths: string[],
+): DiffNode | null => {
-): DiffNode => {
-  if (left === SENTINEL && right !== SENTINEL) {
-    diffPaths.push(path);
-    return {
-      key,
-      type: 'added',
-      oldValue: undefined,
-      newValue: right,
-      path,
-      isLeaf: !isObject(right) && !isArray(right),
-      hasDiffInChildren: false,
-    };
-  }
-
-  if (right === SENTINEL && left !== SENTINEL) {
-    diffPaths.push(path);
-    return {
-      key,
-      type: 'removed',
-      oldValue: left,
-      newValue: undefined,
-      path,
-      isLeaf: !isObject(left) && !isArray(left),
-      hasDiffInChildren: false,
-    };
-  }
-
-  const leftObj = isObject(left);
-  const rightObj = isObject(right);
-  const leftArr = isArray(left);
-  const rightArr = isArray(right);
-
-  if (leftObj && rightObj) {
-    const keySet = new Set<string>();
-    const leftKeys = Object.keys(left);
-    const rightKeys = Object.keys(right);
-
-    for (let i = 0; i < leftKeys.length; i++) keySet.add(leftKeys[i]);
-    for (let i = 0; i < rightKeys.length; i++) keySet.add(rightKeys[i]);
-
-    const children: DiffNode[] = [];
-    keySet.forEach((k) => {
-      const childPath = buildPath(path, k, false);
-      const l: MaybeMissing = k in left ? left[k] : SENTINEL;
-      const r: MaybeMissing = k in right ? right[k] : SENTINEL;
-      children.push(diffNode(l, r, k, childPath, diffPaths));
-    });
-
-    const hasDiffInChildren = children.some((c) => c.type !== 'unchanged' || c.hasDiffInChildren);
-
-    return {
-      key,
-      type: hasDiffInChildren ? 'modified' : 'unchanged',
-      oldValue: left,
-      newValue: right,
-      children,
-      path,
-      isLeaf: false,
-      hasDiffInChildren,
-    };
-  }
-
-  if (leftArr && rightArr) {
-    const len = Math.max(left.length, right.length);
-    const children: DiffNode[] = new Array(len);
-
-    for (let i = 0; i < len; i++) {
-      const k = String(i);
-      const childPath = buildPath(path, k, true);
-      const l: MaybeMissing = i < left.length ? left[i] : SENTINEL;
-      const r: MaybeMissing = i < right.length ? right[i] : SENTINEL;
-      children[i] = diffNode(l, r, k, childPath, diffPaths);
-    }
-
-    const hasDiffInChildren = children.some((c) => c.type !== 'unchanged' || c.hasDiffInChildren);
-
-    return {
-      key,
-      type: hasDiffInChildren ? 'modified' : 'unchanged',
-      oldValue: left,
-      newValue: right,
-      children,
-      path,
-      isLeaf: false,
-      hasDiffInChildren,
-    };
-  }
-
-  const leftIsContainer = leftObj || leftArr;
-  const rightIsContainer = rightObj || rightArr;
-
-  if (!leftIsContainer && !rightIsContainer) {
   if (left === null || right === null) {
     if (left === null && right === null) {
       return {
@@ -140,8 +83,9 @@ const diffNode = (
         hasDiffInChildren: false,
       };
     }
-    } else if (typeof left === typeof right) {
+    return null;
-      if (primitiveEqual(left, right)) {
+  }
+  if (typeof left === typeof right && primitiveEqual(left, right)) {
     return {
       key,
       type: 'unchanged',
@@ -152,27 +96,172 @@ const diffNode = (
       hasDiffInChildren: false,
     };
   }
-    }
+  return null;
-  }
-
-  diffPaths.push(path);
-  return {
-    key,
-    type: 'modified',
-    oldValue: left,
-    newValue: right,
-    path,
-    isLeaf: !leftIsContainer && !rightIsContainer,
-    hasDiffInChildren: false,
-  };
 };
 
 /**
- * 比较两个 JSON 值的差异
+ * 合并对象 key：左全部 + 右独有的（无需 Set，O(K) in 查找）
+ */
+const mergedKeys = (left: Record<string, unknown>, right: Record<string, unknown>): string[] => {
+  const result: string[] = Object.keys(left);
+  for (const k of Object.keys(right)) {
+    if (!(k in left)) result.push(k);
+  }
+  return result;
+};
+
+/**
+ * 比较两个 JSON 值的差异（迭代版，显式栈替代递归）
  */
 export const diffJson = (left: unknown, right: unknown): DiffResult => {
   const diffPaths: string[] = [];
-  const root = diffNode(left, right, '', ROOT_PATH, diffPaths);
+
+  const rootFrame: StackFrame = {
+    left,
+    right,
+    key: '',
+    path: ROOT_PATH,
+    childCount: 0,
+    assembled: false,
+    leftObj: isObject(left),
+    rightObj: isObject(right),
+    leftArr: isArray(left),
+    rightArr: isArray(right),
+    leftIsContainer: isObject(left) || isArray(left),
+    rightIsContainer: isObject(right) || isArray(right),
+  };
+
+  const stack: StackFrame[] = [rootFrame];
+  const resultStack: DiffNode[] = [];
+
+  while (stack.length > 0) {
+    const frame = stack.pop()!;
+
+    // ---- 组装阶段：从 resultStack 弹出子节点 ----
+    if (frame.assembled) {
+      const { childCount } = frame;
+      const children: DiffNode[] = new Array(childCount);
+      // 子节点按正序压入 resultStack，弹出时逆序取
+      for (let i = childCount - 1; i >= 0; i--) {
+        children[i] = resultStack.pop()!;
+      }
+
+      const hasDiffInChildren = children.some((c) => c.type !== 'unchanged' || c.hasDiffInChildren);
+      const type: DiffNode['type'] = hasDiffInChildren ? 'modified' : 'unchanged';
+
+      const node: DiffNode = {
+        key: frame.key,
+        type,
+        oldValue: frame.left === SENTINEL ? undefined : frame.left,
+        newValue: frame.right === SENTINEL ? undefined : frame.right,
+        children,
+        path: frame.path,
+        isLeaf: false,
+        hasDiffInChildren,
+      };
+      resultStack.push(node);
+      continue;
+    }
+
+    const { left: l, right: r } = frame;
+
+    // ---- 一侧缺失 ----
+    if (l === SENTINEL && r !== SENTINEL) {
+      diffPaths.push(frame.path);
+      resultStack.push(createLeafNode(frame.key, frame.path, 'added', undefined, r));
+      continue;
+    }
+    if (r === SENTINEL && l !== SENTINEL) {
+      diffPaths.push(frame.path);
+      resultStack.push(createLeafNode(frame.key, frame.path, 'removed', l, undefined));
+      continue;
+    }
+
+    // ---- 双侧对象 ----
+    if (frame.leftObj && frame.rightObj) {
+      const keys = mergedKeys(l as Record<string, unknown>, r as Record<string, unknown>);
+      // 压入组装帧
+      stack.push({ ...frame, childCount: keys.length, assembled: true });
+      // 逆序压入子帧，保证正序处理
+      for (let i = keys.length - 1; i >= 0; i--) {
+        const k = keys[i];
+        const childPath = buildPath(frame.path, k, false);
+        const leftVal: MaybeMissing =
+          k in (l as Record<string, unknown>) ? (l as Record<string, unknown>)[k] : SENTINEL;
+        const rightVal: MaybeMissing =
+          k in (r as Record<string, unknown>) ? (r as Record<string, unknown>)[k] : SENTINEL;
+        stack.push({
+          left: leftVal,
+          right: rightVal,
+          key: k,
+          path: childPath,
+          childCount: 0,
+          assembled: false,
+          leftObj: isObject(leftVal),
+          rightObj: isObject(rightVal),
+          leftArr: isArray(leftVal),
+          rightArr: isArray(rightVal),
+          leftIsContainer: isObject(leftVal) || isArray(leftVal),
+          rightIsContainer: isObject(rightVal) || isArray(rightVal),
+        });
+      }
+      continue;
+    }
+
+    // ---- 双侧数组 ----
+    if (frame.leftArr && frame.rightArr) {
+      const leftArr = l as unknown[];
+      const rightArr = r as unknown[];
+      const len = Math.max(leftArr.length, rightArr.length);
+
+      stack.push({ ...frame, childCount: len, assembled: true });
+      for (let i = len - 1; i >= 0; i--) {
+        const k = String(i);
+        const childPath = buildPath(frame.path, k, true);
+        const leftVal: MaybeMissing = i < leftArr.length ? leftArr[i] : SENTINEL;
+        const rightVal: MaybeMissing = i < rightArr.length ? rightArr[i] : SENTINEL;
+        stack.push({
+          left: leftVal,
+          right: rightVal,
+          key: k,
+          path: childPath,
+          childCount: 0,
+          assembled: false,
+          leftObj: isObject(leftVal),
+          rightObj: isObject(rightVal),
+          leftArr: isArray(leftVal),
+          rightArr: isArray(rightVal),
+          leftIsContainer: isObject(leftVal) || isArray(leftVal),
+          rightIsContainer: isObject(rightVal) || isArray(rightVal),
+        });
+      }
+      continue;
+    }
+
+    // ---- 原始值比较 ----
+    if (!frame.leftIsContainer && !frame.rightIsContainer) {
+      const primitiveResult = classifyPrimitive(l, r, frame.key, frame.path);
+      if (primitiveResult) {
+        resultStack.push(primitiveResult);
+        continue;
+      }
+    }
+
+    // 类型不同或容器 vs 原始值 → modified
+    diffPaths.push(frame.path);
+    resultStack.push({
+      key: frame.key,
+      type: 'modified',
+      oldValue: l,
+      newValue: r,
+      path: frame.path,
+      isLeaf: !frame.leftIsContainer && !frame.rightIsContainer,
+      hasDiffInChildren: false,
+    });
+  }
+
+  const root = resultStack[resultStack.length - 1];
+
   return {
     root,
     diffPaths,