mobx - 元素描述符的 .kind 属性必须是 "method"或 "field"

Question

我正在关注 mobx-react-router 的文档但是在尝试运行我的应用程序时，我在浏览器中收到以下错误:

Uncaught TypeError: An element descriptor's .kind property must be either "method" or "field", but a decorator created an element descriptor with .kind "undefined"
    at _toElementDescriptor (app.js:49988)
    at _toElementFinisherExtras (app.js:49990)
    at _decorateElement (app.js:49980)
    at app.js:49976
    at Array.forEach (<anonymous>)
    at _decorateClass (app.js:49976)
    at _decorate (app.js:49958)
    at Module../src/App/UserStore.js (app.js:50012)
    at __webpack_require__ (bootstrap:19)
    at Module../src/index.js (index.js:1)

这是我初始化的方式:

const appContainer = document.getElementById('app');
if(appContainer) {
  const browserHistory = createBrowserHistory()
  const routingStore = new RouterStore();

  const stores = {
    users: userStore,
    routing: routingStore
  }

  const history = syncHistoryWithStore(browserHistory, routingStore);

  ReactDOM.render(
    (
      <Provider {...stores}>
        <Router history={history}>
          < App />
        </Router>
      </Provider>
    ),
  appContainer);
}

这就是我的使用方式:

@inject('routing')
@inject('users')
@observer
class App extends Component { ...

我的 UserStore:

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

class UserStore {
  @observable users = [];

  @action addUser = (user) => {
    this.users.push(user)
  }

  @computed get userCount () {
    return this.users.length
  }
}

const store = new UserStore();
export default store;

我已尝试用 Google 搜索此错误，但没有返回任何有用的结果。知道我做错了什么吗？

Answer 1

如果你使用 Babel 7 安装装饰器支持:

npm i -D\
  @babel/plugin-proposal-class-properties\
  @babel/plugin-proposal-decorators

然后在你的 .babelrc 或 webpack.config.js 文件中启用它:

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

请注意，遗留模式很重要(将装饰器提案放在首位也很重要)。非遗留模式是 WIP .

引用:https://mobx.js.org/best/decorators.html