Reactjs, Super expression must either be null or a function

Question

I use the React to write this demo. I use the Webpack to build this demo.When I start this demo, the error will show me.

The error:

Uncaught

Answer 1

The only warning in your code is due the the fact that you are not extending the correct class, you need to extend React.Component.

class App extends React.Component {
        constructor(props){
            super(props);
            this.handleClick = this.handleClick.bind(this);
        }
        handleClick(){
            if(this.myTextInput !=null) {
                this.myTextInput.focus();
            }
        }
        render (){
            return (
                <div>
                    <input type="text" ref={(ref) => this.myTextInput = ref} />
                    <input type="button"
                        value="'Focus the text input"
                           onClick={this.handleClick}
                    />
                </div>
            );
        }
    }
    ReactDOM.render(<App />, document.getElementById('app'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react-dom.min.js"></script>
<div id="app"></div>

Answer 2

try following:

        import React, {Component} from 'react';
        import ReactDOM from 'react-dom';
        class App extends React.Compoment {
          constructor(props){
            super(props);
            this.myTextInput = this.myTextInput.bind(this);
            this.handleClick = this.handleClick.bind(this);
          }
          handleClick(){
            if(this.myTextInput !=null) {
              this.myTextInput.focus();
            }
          }
          render (){
            return (
              <div>
                <input type="text" ref={(ref) => this.myTextInput = ref} />
                <input type="button"
                  value="'Focus the text input"
                  onClick={this.handleClick}
                />
              </div>
            );
          }
        }
        ReactDOM.render(<App />, document.getElementById('app'));