优化trycatch所需的前置知识点(Promise对象讲解)

优化trycatch所需的前置知识点(Promise对象讲解)：https://blog.csdn.net/weixin_45371730/article/details/122029631?spm=1001.2101.3001.6650.9&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7ERate-9-122029631-blog-119996003.235%5Ev38%5Epc_relevant_sort&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7ERate-9-122029631-blog-119996003.235%5Ev38%5Epc_relevant_sort&utm_relevant_index=13