From 87bd8291d5d78e37bd764b32e54c6bcf0b0f0ab0 Mon Sep 17 00:00:00 2001
From: xuwu <zx597813039@gmail.com>
Date: Wed, 10 Mar 2021 07:42:26 +0800
Subject: [PATCH] feat: update answer

---
 Answer/1 ~ 10/2.md | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Answer/1 ~ 10/2.md

diff --git a/Answer/1 ~ 10/2.md b/Answer/1 ~ 10/2.md
new file mode 100644
index 0000000..1663ff4
--- /dev/null
+++ b/Answer/1 ~ 10/2.md	
@@ -0,0 +1,32 @@
+```js
+try {
+    let a = 0
+    ;(async function() {
+        a += 1
+        console.log('inner', a)
+        throw new Error('123')
+        // a()
+    })()
+    console.log('outer', a)
+} catch(e) {
+    console.warn('Error', e)
+}
+```
+
+这道题目基础不好的同学容易答错，很容易以为 `async` 的函数内部代码就是异步的，实际都还是同步的，把代码改成这样大家就明白了：
+
+```js
+function a() {
+  return new Promise(function(resolve, reject) {
+    a += 1
+    console.log('inner', a)
+    throw new Error('123')
+  })
+}
+```
+
+另外发现还有同学疑问为什么 `throw` 出去的错误被 `promise catch` 住了，这个我们直接看标准：
+
+[标准具体地址](https://tc39.es/ecma262/#sec-control-abstraction-objects)
+
+[这里也有一个不错的作答](https://github.com/KieSun/fucking-frontend/issues/2#issuecomment-793266365)