添加 “102.二叉树的层序遍历”Javascript版本

problems/0102.二叉树的层序遍历.md

@@ -687,6 +687,26 @@ func levelOrder(root *TreeNode) [][]int  {
 	return result
 }
 ```
+Javascript:
+```javascript
+var levelOrder = function (root) {
+  let ans = [];
+  if (!root) return ans;
+  let queue = [root];
+  while (queue.length) {
+    let size = queue.length;
+    let temp = [];
+    while (size--) {
+      let n = queue.shift();
+      temp.push(n.val);
+      if (n.left) queue.push(n.left);
+      if (n.right) queue.push(n.right);
+    }
+    ans.push(temp);
+  }
+  return ans;
+};
+```
 
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 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)