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33 lines
876 B
Markdown
33 lines
876 B
Markdown
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```js
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try {
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let a = 0
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;(async function() {
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a += 1
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console.log('inner', a)
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throw new Error('123')
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// a()
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})()
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console.log('outer', a)
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} catch(e) {
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console.warn('Error', e)
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}
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```
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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：
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```js
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function a() {
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return new Promise(function(resolve, reject) {
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a += 1
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console.log('inner', a)
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throw new Error('123')
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})
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}
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```
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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：
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[标准具体地址](https://tc39.es/ecma262/#sec-control-abstraction-objects)
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[这里也有一个不错的作答](https://github.com/KieSun/fucking-frontend/issues/2#issuecomment-793266365)
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