Add js solution to leetcode problem: no.102

Author: lo0b0o

solution/0100-0199/0101.Symmetric Tree/README.md

@@ -115,6 +115,43 @@ private:
     }
 };
 ```
+### **JavaScript**
+
+```js
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number[][]}
+ */
+var levelOrder = function (root) {
+  let result = [];
+  if (!root) return result;
+
+  let queue = [];
+  queue.push(root);
+  while (queue.length) {
+    let size = queue.length;
+    let levelItems = [];
+    while (size--) {
+      let node = queue.shift();
+      levelItems.push(node.val);
+      if (node.left) {
+        queue.push(node.left);
+      }
+      if (node.right) {
+        queue.push(node.right);
+      }
+    }
+    result.push(levelItems);
+  }
+  return result;
+};
 
 ### **...**
 

solution/0100-0199/0102.Binary Tree Level Order Traversal/README_EN.md

@@ -140,6 +140,44 @@ public:
 };
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number[][]}
+ */
+var levelOrder = function (root) {
+  let result = [];
+  if (!root) return result;
+
+  let queue = [];
+  queue.push(root);
+  while (queue.length) {
+    let size = queue.length;
+    let levelItems = [];
+    while (size--) {
+      let node = queue.shift();
+      levelItems.push(node.val);
+      if (node.left) {
+        queue.push(node.left);
+      }
+      if (node.right) {
+        queue.push(node.right);
+      }
+    }
+    result.push(levelItems);
+  }
+  return result;
+};
+
 ### **...**
 
 ```