AppWithReflection.jsx

const DEFAULT_METHODS = ['constructor', 'render', 'componentDidMount', 'componentDidUpdate'];

class App extends React.Component {
  
  constructor() {
    super();
    this.bindMethodsWithContext(this);
    
  }
  
  componentDidMount() {
    //...
  }
  
  componentDidUpdate() {
    //...
  }
  
  bindMethodsWithContext($this) {

    Object.getOwnPropertyNames(App.prototype).forEach((func) => {

      if (DEFAULT_METHODS.indexOf(func) === -1) {
        $this[func] = $this[func].bind($this);
      }

    });

  }
  
  methodA() {
    //...
  }
  
  methodB() {
    //...
  }
    
  methodC() {
    //...
  }
  
  render() {
    //...
  }
  
}