Javascript 语法错误 - 当前未启用对实验性语法“decorators-legacy”的支持

Syntax error - Support for the experimental syntax 'decorators-legacy' isn't currently enabled

提问by olga_babic

I'm trying to build JS react project with decorators. My .babelrc looks like this:

我正在尝试使用装饰器构建 JS react 项目。我的 .babelrc 看起来像这样：

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react",

  ],
  "plugins": [
    "@babel/plugin-transform-runtime",
    "@babel/plugin-transform-object-assign",
    [
      "@babel/plugin-proposal-decorators",
      {
        "legacy": true
      }
    ],
    ["@babel/plugin-proposal-class-properties", { "loose": true }]
  ]
}

Adding @babel/plugin-proposal-decorators problems appears again.

添加@babel/plugin-proposal-decorators 问题再次出现。

I am using babel 7, webpack 4 and react 16.5

我正在使用 babel 7、webpack 4 和 react 16.5

webpack.config.js:

webpack.config.js：

const path = require("path");
const webpack = require("webpack");
const componentName = "reports-desktop";
const publicFolderRelativePath = "../../../../../../public/js";
const ignorePlugin = new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/);

module.exports = {
    entry: './reports-desktop.js'
    ,
    output: {
        path: path.resolve(__dirname, publicFolderRelativePath),
        filename: `${componentName}.js`
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: "babel-loader"
                }
            }
        ]
    },
    plugins: [
        ignorePlugin
    ]
};

package.json:

包.json：

{
  "name": "captain",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "watch": "webpack -w --mode development --progress --color --display-error-details",
    "build": "webpack --mode production"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.0.0",
    "@babel/plugin-proposal-class-properties": "^7.0.0",
    "@babel/plugin-proposal-decorators": "^7.0.0",
    "@babel/plugin-transform-object-assign": "^7.0.0",
    "@babel/plugin-transform-runtime": "^7.0.0",
    "@babel/preset-env": "^7.0.0",
    "@babel/preset-react": "^7.0.0",
    "@babel/preset-stage-1": "^7.0.0",
    "@babel/preset-stage-2": "^7.0.0",
    "babel-loader": "^8.0.2",
    "babel-plugin-transform-decorators": "^6.24.1",
    "react": "^16.5.0",
    "react-dom": "^16.5.0",
    "react-redux": "^5.0.7",
    "react-router-dom": "^4.3.1",
    "redux": "^4.0.0",
    "webpack": "^4.17.3",
    "webpack-cli": "^3.1.0"
  },
  "dependencies": {
    "axios": "^0.18.0",
    "dropzone": "^5.5.1",
    "lodash": "^4.17.10",
    "moment": "^2.22.2",
    "prop-types": "^15.6.2",
    "react-addons-update": "^15.6.2",
    "react-bootstrap": "^0.32.4",
    "react-datetime": "^2.15.0",
    "react-dnd": "^5.0.0",
    "react-dnd-html5-backend": "^5.0.1",
    "react-media": "^1.8.0",
    "react-tooltip": "^3.8.1"
  }
}

Am I maybe using @babel/plugin-proposal-decorators wrong? As it says in documentation this should fix my problem, but it still appears.

我可能使用 @babel/plugin-proposal-decorators 错了吗？正如文档中所说，这应该可以解决我的问题，但它仍然出现。

回答by Christopher Bradshaw

I had the same problem, but I was able to get it working by running npm install --save-dev @babel/plugin-proposal-decoratorsand adding ["@babel/plugin-proposal-decorators", { "legacy": true }]to the plugins section in my .babelrc.

我遇到了同样的问题，但我能够通过运行npm install --save-dev @babel/plugin-proposal-decorators并添加["@babel/plugin-proposal-decorators", { "legacy": true }]到我的.babelrc.

The plugins section of .babelrc, for me, now looks like this:

.babelrc对我来说，插件部分现在看起来像这样：

"plugins": [
  ["@babel/plugin-proposal-decorators", { "legacy": true }]
]

回答by Alex Cory

Taken from mobxjs. If you're still having issues refer to this. It helped me.

取自mobxjs。如果您仍然遇到问题，请参阅此。它帮助了我。

Example config for babel 7, in decorators legacy mode:

babel 7 的示例配置，在装饰器遗留模式下：

//.babelrc

{
    "presets": ["@babel/preset-env"],
    "plugins": [
        ["@babel/plugin-proposal-decorators", { "legacy": true }],
        ["@babel/plugin-proposal-class-properties", { "loose": true }]
    ]
}

Please note that plugin ordering is important, and plugin-proposal-decorators should be the first plugin in your plugin list

请注意插件顺序很重要，plugin-proposal-decorators 应该是你插件列表中的第一个插件

"devDependencies": {
    "@babel/core": "^7.1.0",
    "@babel/plugin-proposal-class-properties": "^7.1.0",
    "@babel/plugin-proposal-decorators": "^7.1.0",
    "@babel/preset-env": "^7.1.0"
}

Non-legacy mode decorators (stage 2) is work in progress, see #1732

非传统模式装饰器（第 2 阶段）正在进行中，请参阅 #1732

Edit: updated config to show the non-beta configuration for babel 7

编辑：更新配置以显示 babel 7 的非测试版配置

回答by Abhay Kumar

If you face this error while using ReactJS with MobX, don't enable decorator syntax, but leverage the MobX's built-in decorate utility to apply decorators to your classes / objects.

如果您在将 ReactJS 与 MobX 一起使用时遇到此错误，请不要启用装饰器语法，而是利用 MobX 的内置装饰实用程序将装饰器应用于您的类/对象。

Don't:

别：

import { observable, computed, action } from "mobx";

class Timer {
  @observable start = Date.now();
  @observable current = Date.now();

  @computed
  get elapsedTime() {
    return this.current - this.start + "milliseconds";
  }

  @action
  tick() {
    this.current = Date.now();
  }
}

Do:

做：

import { observable, computed, action, decorate } from "mobx";

class Timer {
  start = Date.now();
  current = Date.now();

  get elapsedTime() {
    return this.current - this.start + "milliseconds";
  }

  tick() {
    this.current = Date.now();
  }
}
decorate(Timer, {
  start: observable,
  current: observable,
  elapsedTime: computed,
  tick: action
});

回答by ulyC

First, execute the command:

首先，执行命令：

npm install customize-cra react-app-rewired @babel/plugin-proposal-decorators --save

npm install customize-cra react-app-rewired @babel/plugin-proposal-decorators --save

Create a new file config-overrides.jsat project root and then execute the following:

config-overrides.js在项目根目录创建一个新文件，然后执行以下命令：

const { override, addDecoratorsLegacy } = require('customize-cra');
module.exports = override(
 addDecoratorsLegacy()
 );

Also, edit your package.jsonfile ：

另外，编辑你的package.json文件：

"scripts": {
 "start": "react-app-rewired start",
 "build": "react-app-rewired build",
 "test": "react-app-rewired test",
 "eject": "react-app-rewired eject"
  },

then restart.

然后重新启动。

回答by wuliwong

I fixed this with yarn add @babel/plugin-proposal-decorators

我用 yarn add @babel/plugin-proposal-decorators

Then I added the following to babel.config.jsin the pluginssection:

然后我babel.config.js在该plugins部分添加了以下内容：

  [
    require('@babel/plugin-proposal-decorators').default,
    {
      legacy: true
    }
  ],

Finally I needed to restart my webpack dev server.

最后我需要重新启动我的 webpack 开发服务器。

---

---

I haven't tested this but like @christopher bradshaw answers says and according to the babel website if you are using .babelrcfor configuration then add the following to the "plugins"section:

我还没有测试过这个，但就像@christopher bradshaw 回答说的那样，根据 babel 网站，如果您.babelrc用于配置，则将以下内容添加到该"plugins"部分：

  ["@babel/plugin-proposal-decorators", { "legacy": true }]

回答by VahidN

Unfortunately none of the mentioned solutions worked for me. Because they need you to run npm run ejectfirst and ... I don't want to do that. To change and override the webpack's configs at runtime, there's a package called react-app-rewiredand this is how it should be used:

不幸的是，上述解决方案都不适用于我。因为他们需要你先跑npm run eject……我不想那样做。要在运行时更改和覆盖 webpack 的配置，有一个包被调用react-app-rewired，这就是它的使用方式：

First install the required dependencies:

首先安装所需的依赖项：

npm i --save-dev customize-cra react-app-rewired

Then add a new file called config-overrides.jsto the root folder of the project with this content to enable legacy decorators babel plugin:

然后config-overrides.js在项目的根文件夹中添加一个新文件，该文件包含此内容以启用旧式装饰器 babel 插件：

const {
  override,
  addDecoratorsLegacy,
  disableEsLint
} = require("customize-cra");

module.exports = override(
  // enable legacy decorators babel plugin
  addDecoratorsLegacy(),

  // disable eslint in webpack
  disableEsLint()
);

Finally change the package.jsonfile to use react-app-rewired:

最后更改package.json要使用的文件react-app-rewired：

  "scripts": {
    "start": "react-app-rewired start",
    "build": "react-app-rewired build",
    "test": "react-app-rewired test",
    "eject": "react-app-rewired eject"
  },

Now run the npm startas usual and enjoy it!

现在npm start像往常一样运行并享受它！

回答by zloctb

package.json

包.json

"@babel/core": "^7.2.2",
"@babel/plugin-proposal-class-properties": "^7.1.0",
"@babel/plugin-proposal-decorators": "^7.1.0",
"@babel/preset-env": "^7.2.3",
"@babel/preset-react": "^7.0.0",
"@babel/register": "^7.0.0",
"babel-loader": "^8.0.5"

webpack.config.js

webpack.config.js

presets: ["@babel/preset-env", "@babel/preset-react"]

.babelrc

.babelrc

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react"
  ],
  "plugins":  [
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    ["@babel/plugin-proposal-class-properties", { "loose": true }]
  ]
}

回答by Anton Matiashevich

Renamed .babelrcto babel.config.jsonand it worked!!!

重命名.babelrc为babel.config.json，它起作用了！！！

回答by Ati Barzideh

I tried to install babel-plugin-transform-inline-environment-variablesand it worked.

我尝试安装babel-plugin-transform-inline-environment-variables并且成功了。

npm install babel-plugin-transform-inline-environment-variables