Question

React和javascript的新功能。我正在研究它，我试图从React客户端的服务器获取一个字符串并显示它。我的代码如下

server.js

const express = require('express');

const app = express();
app.set("port", process.env.PORT || 3001 )

app.use(express.static("ayersapp/build"));

app.get('/message', (req, res) => {
    res.send('Hello first respond!');
});

app.listen(app.get("port"));

App.js

import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
import Message from './message'

class App extends Component {
  render() {
    return (
      <div className="App">
        <header className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h1 className="App-title">Welcome to React</h1>
        </header>
        <p className="App-intro">
          To get started, edit <code>src/App.js</code> and save to reload.
        </p>
        <Message />
      </div>
    );
  }
}

export default App;

message.js

import React, {Component} from 'react';

class Message extends Component {
    constructor(props) {
        super(props);
        this.state = {message: "abc"};
    }

    componentDidMount() {
        fetch(`/message`).then(m=>{
            this.setState(
                {message: m.blob()}
            );
        });
    }

    render(){
        const msg = this.state.message;
        return <p>{msg}</p>;
    }
}

export default Message;

来自here我可以使用.then（（）=＆gt; {}）访问字符串数据。但是我收到了这个错误

Objects are not valid as a React child (found: [object Promise]). If you meant to render a collection of children, use an array instead.
    in p (at message.js:19)
    in Message (at App.js:17)
    in div (at App.js:9)
    in App (at index.js:7)

有人能让我知道如何访问对象Promise中的字符串吗？

Answer 1

试试这个：

fetch('https://jsonplaceholder.typicode.com/posts/1')
    .then(response => response.text())
    .then(text => {
        console.log('text = ', text)
//             this.setState({
//                  message: text
//             })

     })

如何访问fetch（）返回的响应中的文本？

1 个答案: