update: Use function declarations instead of function expressions. (#385)

Co-authored-by: steak-zhuo <zhuoqinyue@gmail.com>

codes/javascript/chapter_graph/graph_bfs.js

@@ -11,7 +11,7 @@ const { Vertex } = require('../include/Vertex');
 
 /* 广度优先遍历 BFS */
 // 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
-const graphBfs = (graph, startVet) => {
+function graphBfs(graph, startVet) {
     // 顶点遍历序列
     const res = [];
     // 哈希表，用于记录已被访问过的顶点