Higher-order Components

Enhance.js

import { Component } from "React";

export var Enhance = ComposedComponent => class extends Component {
  constructor() {
    this.state = { data: null };
  }
  componentDidMount() {
    this.setState({ data: 'Hello' });
  }
  render() {
    return <ComposedComponent {...this.props} data={this.state.data} />;
  }
};

HigherOrderComponent.js

import { Enhance } from "./Enhance";

class MyComponent {
  render() {
    if (!this.data) return <div>Waiting...</div>;
    return <div>{this.data}</div>;
  }
}

export default Enhance(MyComponent); // Enhanced component

Wow, the React community really flubbed on terminology here. In this gist, the component utilizing what we call the HoC is called the HoC, whereas the thing we call the HoC is called an "Enhancer." This makes way more sense, as a "HoC," as it is known today, is not itself a component at all. Sad!!

Not quite see the difference between HoC and old decorator pattern. I would say HoC is a nice react implementation of decorator pattern.

Your constructor needs super(props) as the first line