× Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object

× Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object

请帮我解决这个错误: 错误:元素类型无效:应为字符串(对于内置组件)或 class/function(对于复合组件)但得到:对象。 这是我的代码:

index.js: 

import ReactDOM from 'react-dom';
import './index.css'
import reportWebVitals from './reportWebVitals';
import ApolloProvider from './ApolloProvider'

ReactDOM.render(

  <
  ApolloProvider / > ,
  document.getElementById('root')
);
reportWebVitals();

ApolloProvider.js:

import React from 'react'
import App from './App'
import ApolloClient from 'apollo-client'
import {
  InMemoryCache
} from 'apollo-cache-inmemory'
import {
  createHttpLink
} from 'apollo-link-http'
import {
  ApolloProvider
} from '@apollo/react-hooks'

const httpLink = createHttpLink({
  uri: 'http//localhost:5000'
})

const client = new ApolloClient({
  link: httpLink,
  cache: new InMemoryCache()
})

export default ( <
  ApolloProvider client = {
    client
  } >
  <
  App / >
  <
  /ApolloProvider>
);

尝试

ReactDOM.render(
  ApolloProvider ,
  document.getElementById('root')
);

或更新提供商以导出组件

export default function provider() {
return (
  <ApolloProvider client={client}>
    <App />
  </ApolloProvider>
);
}