简体   繁体   中英

Render DOM element in REACT js

I have installed fresh react js on local as:

npm install -g create-react-app
create-react-app hello-world
cd hello-world
npm start

App.js:

import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
import ReactDOM from 'react-dom';

class App extends Component {
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>

        </div>
        <div id="root"></div>
        <div id="test"></div>
        <p className="App-intro">
          To get started, edit <code>src/App.js</code> and save to reload.
        </p>

      </div>
    );
  }
}

ReactDOM.render(
  <h1>Hello, world Root!</h1>,
  document.getElementById('root')
);

ReactDOM.render(
  <h1>Hello, world Test!</h1>,
  document.getElementById('test')
);

export default App;

index.html:

    <body>
    <div id="root"></div>
    <div id="test"></div>
    <!--
      This HTML file is a template.
      If you open it directly in the browser, you will see an empty page.

      You can add webfonts, meta tags, or analytics to this file.
      The build step will place the bundled scripts into the <body> tag.

      To begin the development, run `npm start`.
      To create a production bundle, use `npm run build`.
    -->
  </body>
  • The issue is that i am able to print only Hello, world Test! and not Hello, world Root! although I am not getting any error too means it is a DOM element than way i am not getting any thing. I inspected it also and their also it is not rendering.

  • Also one more thing I added div with id 'test' in index.html so it a fine approach to add div in that.

  • I am new to React any help please.

Answer to your question:

The render is already stand for ReactDOM.render, is the same thing, so in the tutorial, it is like

ReactDOM.render(
  <h1>Hello, world!</h1>,
  document.getElementById('root')
);

which is the same as

render() {
  return (
    <h1>Hello, world!</h1>
  )
}

React little tutorial: Is a plain HTML without state and props, i guess you are doing simply like this.

import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
import ReactDOM from 'react-dom';

class App extends Component {
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        </div>

        <div id="root">
          <h1>Hello, world Root!</h1>
        </div>

        <div id="test">
          <h1>Hello, world Test!</h1>
        </div>

        <p className="App-intro">
          To get started, edit <code>src/App.js</code> and save to reload.
        </p>
      </div>
    );
  }
}

export default App;

To use state/props, you can do something like:

state :

constructor() {
  super();
  this.state = {
    text: "Hello, world Root!"
  };
}

replace the text with:

<div id="test">
  <h1>{this.state.text}</h1>
</div>

And similarly, if you have props = "Hello, world Root!", you can:

props :

<div id="root">
  <h1>{this.props.root}</h1>
</div>

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM