React Apollo Client useQuery Hook gql Uncaught TypeError:(...) is not a function

Question

所以我想使用 Apollo Client react hook "useQuery" 来查询我的 graphql 后端运行 Apollo Server。

但是定义的查询常量 return 会给我一个错误：Uncaught TypeError:(...) is not a function and thus the page is not rendering at all.

我的 ApolloClient 和 Provider 设置如下：

index.js:

import React from 'react';
import { render } from 'react-dom';
import { BrowserRouter as Router } from 'react-router-dom';
import { ApolloClient } from 'apollo-client';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { HttpLink } from 'apollo-link-http';
import { onError } from 'apollo-link-error';
import { ApolloLink, from } from 'apollo-link';
import { ApolloProvider } from 'react-apollo';
import { createUploadLink } from 'apollo-upload-client';

import 'bootstrap/dist/css/bootstrap.min.css';
import App from './components/App';
import './index.css';

const uploadLink = createUploadLink({ uri: process.env.REACT_APP_API_URL });
const httpLink = new HttpLink({
  uri: process.env.REACT_APP_API_URL,
  credentials: 'same-origin'
});
const cache = new InMemoryCache();

const client = new ApolloClient({
  link: ApolloLink.from([
    onError(({ graphQLErrors, networkError }) => {
      if (graphQLErrors)
        graphQLErrors.forEach(({ message, locations, path }) =>
          console.log(
            `[GraphQL error]: Message: ${message}, Location: ${locations}, Path: ${path}`
          )
        );
      if (networkError) console.log(`[Network error]: ${networkError}`);
    }),
    httpLink,
    uploadLink
  ]),
  cache,
  uri: process.env.REACT_APP_API_URL
});

render(
  <ApolloProvider client={client}>
    <Router>
      <App />
    </Router>
  </ApolloProvider>,
  document.getElementById('app')
);

App 组件将触发查询：

components/game/GamePage.js:

import React, { Component } from 'react';
// import GameForm from './gameform';
import GameRules from './gamerules';
// import PropTypes from 'prop-types';

import { gql } from 'graphql-tag';
import { useQuery } from '@apollo/react-hooks';

class GamePage extends Component {
  constructor(props) {
    super(props);
    this.handleSubmit = this.handleSubmit.bind(this);

    this.GET_ALL_PLAYERS = gql`
      query allPlayers {
        allPlayers {
          id
          name
          nickname
        }
      }
    `;
  }
  state = { selectedGame: 'X01' };

  componentDidMount() {
    // const players = this.props;
    // players.loadPlayers().catch(err => {
    //   alert('Loading players failed. ' + err);
    // });

    const { loading, error, data } = useQuery(this.GET_ALL_PLAYERS);

    if (loading) console.log('Loading...');
    if (error) console.log(`Error! ${error.message}`);
    console.log(data);
  }

  handleSubmit = gameObject => {
    console.log(gameObject);
    // this.props.createGame(gameObject);
  };

  handleGameChange = game => {
    this.setState({
      selectedGame: game
    });
  };

  render() {
    const styles = {
      margin: '20px'
    };

    return (
      <div className="container-fluid">
        <div className="row">
          <div className="col-md-6">
            <h2 style={styles}>Game Setup</h2>
            {/* <GameForm
              players={this.props.players}
              onSubmit={this.handleSubmit}
              onGameChange={this.handleGameChange}
            /> */}
          </div>
          <div className="col-md-6">
            <h2 style={styles}>Game Rules</h2>
            <GameRules game={this.state.selectedGame} />
          </div>
        </div>
      </div>
    );
  }
}

// GamePage.propTypes = {
//   players: PropTypes.array,
//   games: PropTypes.array,
//   createGame: PropTypes.func.isRequired
// };

export default GamePage;

加载应用程序时会出现上述错误。我像在 2 小时内使用谷歌搜索和 youtubing 找到的所有教程一样进行了学习。但我无法自己解决。此外，后端工作正常。用ApolloServer的Webserver测试工具测试过。

有问题的部分是这样的：

this.GET_ALL_PLAYERS = gql`
  query playersList {
    allPlayers {
      id
      name
      nickname
    }
  }
`;

以下是我收到的错误图片：

因此，我们将不胜感激。谢谢

编辑：将 {gql} 导入更改为 gql 后出现新错误

Answer 1

如果没有看到您的完整错误（包括跟踪），很难确定，但我怀疑您没有正确导入 from。 apollo-link 模块确实导出了一个名为 ApolloLink 的 class，但是这个 class 没有名为 from 的静态方法。相反，您正在寻找来自同一模块的另一个命名导出：

import { from } from 'apollo-link'

另请注意，react-apollo-hooks 模块现已弃用，因为挂钩 API 现在是 react-apollo 的一部分。您应该升级 react-apollo 并仅将单个 ApolloProvider 用于挂钩和任何遗留组件。

编辑：

查看您的错误，问题出在 GamePage 构造函数内部（注意第一行是 at new GamePage）。同样，这里有一个导入问题，因为 graphql-tag 没有名为 gql 的命名导入。该模块只有文档中所示的默认导出：

import gql from 'graphql-tag'

React Apollo Client useQuery Hook gql Uncaught TypeError:(...) is not a function

React Apollo Client useQuery Hook gql Uncaught TypeError:(...) is not a function

javascript

reactjs

graphql

react-hooks

react-apollo