Javascript babel 6 异步/等待：意外的令牌
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babel 6 async / await: Unexpected token
提问by legomind
Im having trouble getting async / await transforms working. What am I missing?
我无法让异步/等待转换工作。我错过了什么？
My .babelrc:
我的 .babelrc：
{
"presets": [ "es2015", "stage-0" ]
}
My package.json (snipped):
我的 package.json （剪下）：
{
"babel-core": "^6.1.2",
"babel-plugin-transform-runtime": "^6.1.2",
"babel-preset-es2015": "^6.1.2",
"babel-preset-stage-0": "^6.1.2"
}
Output:
输出：
babel src/server
SyntaxError: src/server/index.js: Unexpected token (7:21)
5 |
6 | try {
> 7 | let server = await server('localhost', env.NODE_PORT || 3000)
| ^
8 | console.log(`Server started on ${server.info.uri}`)
9 | } catch (err) {
10 | console.error('Error starting server: ', err)
回答by Yormi
According to this post you need to have babel-polyfill
根据这篇文章，你需要有 babel-polyfill
Babel 6 regeneratorRuntime is not defined with async/await
Babel 6 regeneratorRuntime 没有用 async/await 定义
Hopefully it'll help you :)
希望它会帮助你:)
EDIT:
编辑：
It doesn't have to be babel-polyfill but it's the only one I used.
它不一定是 babel-polyfill，但它是我唯一使用的。
As Gothdo said: the awaitkeyword has to be in a function scope. Moreover, this function definition has to have the asynckeyword.
正如 Gothdo 所说：await关键字必须在函数范围内。而且，这个函数定义必须有async关键字。
This means that you can not have the awaitkeyword on the top-level scope.
这意味着您不能await在顶级范围内使用关键字。
回答by Allain Lalonde
Looks like async/await is only available in babel-preset-stage-3
看起来 async/await 仅适用于 babel-preset-stage-3
回答by Madole
You can compile them yourself using the transform-async-to-module-methodplugin, this allows you to compile them down to bluebird co-routines which requires ES6 generators (available in node4).
您可以使用transform-async-to-module-method插件自己编译它们，这允许您将它们编译为需要 ES6 生成器（在 node4 中可用）的 bluebird 协程。
Or if you need to compile it back to ES5 so it's compatible for browsers you can use transform-async-to-generatorand facebook's regenerator.
或者，如果您需要将其编译回 ES5，以便与您可以使用的浏览器transform-async-to-generator和 facebook 的regenerator.
I've written about how to set up your babel config here http://madole.xyz/async-await-es7/
我已经在http://madole.xyz/async-await-es7/写了关于如何设置你的 babel 配置的文章
回答by Beder Acosta Borges
Use the Async to generator transform.
使用Async 到生成器转换。
Installation
安装
$ npm install babel-plugin-transform-async-to-generator
Usage
用法
Add the following line to your .babelrcfile:
将以下行添加到您的.babelrc文件中：
{
"plugins": ["transform-async-to-generator"]
}
回答by Tamizaan
It's recommended to upgrade to Babel 7 and use babel-env as opposed to stages (see here: https://github.com/babel/babel-upgrade).
建议升级到 Babel 7 并使用 babel-env 而不是阶段（请参阅此处：https: //github.com/babel/babel-upgrade）。
There's a command you can use to upgrade accordingly:
有一个命令可以用来相应地升级：
npx babel-upgrade
