Question

我创建了以下高阶组件：

const baseComponent = (WrappedComponent: React.ComponentClass<any>) => (props: IKeyValue) => {
  if (props.isLoading) {
    return (
      <LoadingSpinnerComponent shown={true} />
    );
  }

  return (
    <WrappedComponent {...props} />
  );
};

这导致无限期地调用此组件。（componentDidMount中的myComponent表示正在重新创建此组件。

我以下列方式使用它：

export default connect(
  mapStateToProps,
  dispatchToProps,
)(baseComponent(myComponent)) as React.ComponentClass<any>;

删除if部分时：

  if (props.isLoading) {
    return (
      <LoadingSpinnerComponent shown={true} />
    );
  }

该组件只会被调用一次。我试图深入调试反应lib代码，但魔术对我来说是一个奇迹。有什么想法吗？

提前致谢！

编辑：

完整代码： myComponent：

class MiniCatalogContainer extends React.PureComponent<IProps, void> {
  public componentDidMount() {
    const { fetchCatalog} = this.props;
    fetchCatalog({path});
  }

  public render() {
    ...
  }
}

export default connect(
  mapStateToProps,
  dispatchToProps,
)(baseComponent(MyComponent)) as React.ComponentClass<any>;

promise-middleware

import { Dispatch } from 'react-portal/src/interfaces';
import isPromise from 'react-portal/src/utils/is-promise';

interface IOptions {
  dispatch: Dispatch;
}

export default function promiseMiddleware({ dispatch }: IOptions) {
  return (next: Dispatch) => (action: any) => {
    if (!isPromise(action.payload)) {
      return next(action);
    }

    const { types, payload, meta } = action;
    const { promise, data } = payload;
    const [ PENDING, FULFILLED, REJECTED ] = types;

   /**
    * Dispatch the pending action
    */
    dispatch( { type: PENDING,
                ...(data ? { payload: data } : {}),
                ...(meta ? { meta } : {}),
    });

    /**
     * If successful, dispatch the fulfilled action, otherwise dispatch
     * rejected action.
     */
    return promise.then(
      (result: any) => {
        dispatch({
          meta,
          payload: result,
          type: FULFILLED,
        });
      },
      (error: any) => {
        dispatch({
          meta,
          payload: error,
          type: REJECTED,
        });
      },
    );
  };
}

解决方案：

正如@Shleng注意到的那样，循环是因为我在组件内部进行了fetch调用。我最终得到了简单的解决方案：

const baseComponent = (WrappedComponent: React.ComponentClass<any>) => (props: IKeyValue) => {
      if (props.isLoading) {
        return (
          <LoadingSpinnerComponent shown={true} />
          <WrappedComponent {...props} />
        );
      }

      return (
        <WrappedComponent {...props} />
      );
    };

Answer 1

因为您在包裹的组件fetchCatalog内调用了componentDidMount，所以工作流会产生如下所示的循环：

mount WrappedComponent -> fetch -> mount Spinner -> loaded -> mount WrappedComponent -> fetch (loop!)

isLoading: false       -> true                   -> false                            -> true

多次调用高阶分量

1 个答案: