Babel 意外令牌编译反应组件

Question

我正在尝试使用 babel 编译以下代码，但它在下一行的字符“=”上给了我一个 "unexpected token"：

状态 = {}；

Babel 版本为：6.24.1 (babel-core 6.25.0)

代码：

import {Button, Menu} from 'semantic-ui-react';

class AppBar extends Component {
    state = {};

    handleItemClick = (e, { name }) => this.setState({ activeItem: name });

    render() {
        const { activeItem } = this.state;

        return (
            <Menu>
                <Menu.Item
                    name='dashboard'
                    active={activeItem === 'dashboard'}
                    onClick={this.handleItemClick}
                >
                    Dashboard
                </Menu.Item>

                <Menu.Item
                    name='contacts'
                    active={activeItem === 'contacts'}
                    onClick={this.handleItemClick}
                >
                    Contact Lists
                </Menu.Item>

                <Menu.Item
                    name='messages'
                    active={activeItem === 'messages'}
                    onClick={this.handleItemClick}
                >
                    Messages
                </Menu.Item>
            </Menu>
        )
    }
}

ReactDOM.render(
  <AppBar/>,
  document.getElementById('root')
);

我正在使用 es2015 和 React 预设。

有什么问题？谢谢

Answer 1

将包 babel-plugin-transform-class-properties 添加到您的项目。

Answer 2

我目前正在为我们的 React 应用程序使用这些 babel 模块（在 package.json 中）：

"babel-cli": "~6.24.1",
"babel-core": "~6.25.0",
"babel-eslint": "~7.2.3",
"babel-loader": "~7.1.0",
"babel-plugin-add-module-exports": "~0.2.1",
"babel-plugin-istanbul": "^4.1.3",
"babel-plugin-syntax-dynamic-import": "^6.18.0",
"babel-plugin-transform-class-properties": "~6.24.1",
"babel-preset-es2015": "~6.24.1",
"babel-preset-react": "~6.24.1",
"babel-preset-stage-3": "^6.24.1",
"babel-register": "~6.24.1",
"babel-runtime": "~6.23.0",

我在根文件夹中有以下 .bablerc：

{
  "presets": [
    "es2015", "react", "stage-3"
  ],
  "plugins": ["transform-class-properties", "add-module-exports","syntax-dynamic-import"],
  "env": {
    "development": {
      "plugins": ["react-hot-loader/babel"]
    },
    "coverage": {
      "plugins": ["istanbul"]
    }
  }
}

我用同样的代码定义了state

export class AttributeModelListContainer extends React.Component {

  static propTypes = {
    // from router
    params: PropTypes.shape({
      project: PropTypes.string,
    }),
    // from mapStateToProps
    [...]
  }

  state = {
    isLoading: true,
  }
}

Answer 3

确保你已经安装了你需要的所有 babel 预设：

yarn add babel-loader babel-core --dev
yarn add babel-polyfill --dev
yarn add babel-preset-es2015 --dev
yarn add babel-preset-stage-2 --dev
yarn add babel-preset-react --dev

而 babel 按以下顺序预设为 .babelrc：

{
  "presets": ["es2015", "react", "stage-2"]
}

Include stage-2 应具有您开发所需的足够新功能。

Babel 意外令牌编译反应组件

Babel unexpected token compiling react component

ecmascript-6

reactjs

babeljs

semantic-ui-react