leporello-js/docs/examples/preact/stateful.js

import {Component} from 'https://unpkg.com/preact?module';

export const Stateful = ({getInitialState, handlers, render}) => {

  return class extends Component {

    constructor() {
      super()
      this.compState = getInitialState()
      this.handlers = Object.fromEntries(
        Object
          .entries(handlers)
          .map(([name, h]) => 
            [name, this.makeHandler(h)]
          )
      )
    }

    makeHandler(h) {
      return (...args) => {
        this.compState = h(this.compState, ...args)
        this.forceUpdate()
      }
    }

    render() {
      return render(this.props, this.compState, this.handlers)
    }
  }

}