Javascript SyntaxError：意外的令牌函数 - Async Await Nodejs

SyntaxError: Unexpected token function - Async Await Nodejs

提问by bozzmob

I was experimenting on using Node version 6.2.1with some of my code. Had plans to migrate most of the hyper-callback oriented codes to something that looks cleaner and maybe performs better.

我正在尝试将 Node 6.2.1版与我的一些代码一起使用。曾计划将大多数面向超级回调的代码迁移到看起来更干净并且性能可能更好的东西。

I have no clue why, the terminal throws up an error when I try to execute the node code.

我不知道为什么，当我尝试执行节点代码时终端会抛出错误。

helloz.js

hello.js

(async function testingAsyncAwait() {
    await console.log("Print me!");
})();

Logs-

日志-

BOZZMOB-M-T0HZ:rest bozzmob$ node helloz.js 
/Users/bozzmob/Documents/work/nextgennms/rest/helloz.js:1
(function (exports, require, module, __filename, __dirname) { (async function testingAsyncAwait() {
                                                                     ^^^^^^^^
SyntaxError: Unexpected token function
    at Object.exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:513:28)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
    at Function.Module.runMain (module.js:575:10)
    at startup (node.js:160:18)
    at node.js:456:3
BOZZMOB-M-T0HZ:rest bozzmob$ node -v
v6.2.1

What am I missing? Please throw me some light on the same.

我错过了什么？请给我一些启发。

---

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Update 1:

更新 1：

I tried to use Babel as Quentin suggested, But, I am getting the following error still.

我尝试按照 Quentin 的建议使用 Babel，但是，我仍然收到以下错误。

Updated Code-

更新代码-

require("babel-core/register");
require("babel-polyfill");

    (async function testingAsyncAwait() {
        await console.log("Print me!");
    })();

Logs-

日志-

BOZZMOB-M-T0HZ:rest bozzmob$ babel helloz.js > helloz.trans.js
SyntaxError: helloz.js: Unexpected token (3:7)
  1 | require("babel-polyfill");
  2 | 
> 3 | (async function testingAsyncAwait() {
    |        ^
  4 |     await console.log("Print me!");
  5 | })();

回答by Quentin

Async functions are not supported by Node versions older than version 7.6.

低于 7.6 的 Node 版本不支持异步函数。

You'll need to transpile your code (e.g. using Babel) to a version of JS that Node understands if you are using an older version.

如果您使用的是旧版本，您需要将您的代码（例如使用Babel）转换为 Node 能够理解的 JS 版本。

That said, the current (2018) LTSversion of Node.js is 8.x, so if you are using an earlier version you should very strongly consider upgrading.

也就是说，Node.js的当前 (2018) LTS版本是 8.x，因此如果您使用的是早期版本，则应强烈考虑升级。

回答by Phillipe Moreira

Nodejs supports async/await from version 7.6.

Nodejs 从 7.6 版开始支持 async/await。

Release post: https://v8project.blogspot.com.br/2016/10/v8-release-55.html

发布帖：https: //v8project.blogspot.com.br/2016/10/v8-release-55.html

回答by Nivesh

Node.JS does not fully support ES6 currently, so you can either use asyncawaitmodule or transpileit using Bable.

Node.JS 目前不完全支持 ES6，所以你可以使用asyncawait模块或使用Bable转译它。

install

安装

npm install --save asyncawait

helloz.js

hello.js

var async = require('asyncawait/async');
var await = require('asyncawait/await');

(async (function testingAsyncAwait() {
    await (console.log("Print me!"));
}))();

回答by stujo

If you are just experimenting you can use babel-nodecommand line tool to try out the new JavaScript features

如果您只是在试验，您可以使用babel-node命令行工具来尝试新的 JavaScript 功能

1. Install babel-cliinto your project

   $ npm install --save-dev babel-cli

2. Install the presets

   $ npm install --save-dev babel-preset-es2015 babel-preset-es2017

3. Setup your babel presets

   Create .babelrcin the project root folder with the following contents:

   { "presets": ["es2015","es2017"] }

4. Run your script with babel-node

   $ babel-node helloz.js

1. 安装babel-cli到你的项目中

   $ npm install --save-dev babel-cli

2. 安装预设

   $ npm install --save-dev babel-preset-es2015 babel-preset-es2017

3. 设置你的 babel 预设

   .babelrc在项目根文件夹中创建，内容如下：

   { "presets": ["es2015","es2017"] }

4. 运行你的脚本 babel-node

   $ babel-node helloz.js

This is only for development and testing but that seems to be what you are doing. In the end you'll want to set up webpack (or something similar) to transpile all your code for production

这仅用于开发和测试，但这似乎是您正在做的。最后你会想要设置 webpack（或类似的东西）来转译你所有的生产代码

• babel-node sample code : https://github.com/stujo/javascript-async-await/tree/15abac

• babel-node 示例代码：https: //github.com/stujo/javascript-async-await/tree/15abac

If you want to run the code somewhere else, webpack can help and here is the simplest configuration I could work out:

如果你想在其他地方运行代码，webpack 可以提供帮助，这是我能解决的最简单的配置：

• Full webpack example : https://github.com/stujo/javascript-async-await

• 完整的 webpack 示例：https: //github.com/stujo/javascript-async-await

回答by slideshowp2

node v6.6.0

node v6.6.0

If you just use in development. You can do this:

如果你只是在开发中使用。你可以这样做：

npm i babel-cli babel-plugin-transform-async-to-generator babel-polyfill --save-dev

the package.jsonwould be like this:

该package.json会是这样：

"devDependencies": {
   "babel-cli": "^6.18.0",
   "babel-plugin-transform-async-to-generator": "^6.16.0",
   "babel-polyfill": "^6.20.0"
}

create .babelrcfile and write this:

创建.babelrc文件并写入：

{
  "plugins": ["transform-async-to-generator"]
}

and then, run your async/awaitscript like this:

然后，async/await像这样运行你的脚本：

./node_modules/.bin/babel-node script.js

回答by Theophilus Omoregbee

Though I'm coming in late, what worked for me was to install transform-async-generatorand transform-runtimeplugin like so:

虽然我来晚了，但对我有用的是安装transform-async-generator和transform-runtime插件，如下所示：

npm i babel-plugin-transform-async-to-generator babel-plugin-transform-runtime --save-dev

npm i babel-plugin-transform-async-to-generator babel-plugin-transform-runtime --save-dev

the package.jsonwould be like this:

该package.json会是这样：

"devDependencies": {
   "babel-plugin-transform-async-to-generator": "6.24.1",
   "babel-plugin-transform-runtime": "6.23.0"
}

create .babelrcfile and write this:

创建.babelrc文件并写入：

{
  "plugins": ["transform-async-to-generator", 
["transform-runtime", {
      "polyfill": false,
      "regenerator": true
    }]
]
}

and then happy coding with async/await

然后愉快地编码 async/await

回答by Githithu Wambura

include and specify the node engine version to the latest, say at this time I did add version 8.

包含并指定最新的节点引擎版本，比如我此时确实添加了版本 8。

{
  "name": "functions",
  "dependencies": {
    "firebase-admin": "~7.3.0",
    "firebase-functions": "^2.2.1",
  },
  "engines": {
    "node": "8"
  },
  "private": true
}

in the following file

在以下文件中

package.json

包.json