observer-component.js

import { Component } from 'react'
import { observe } from '@nx-js/observer-util'

export default class ObserverComponent extends Component {

  componentWillMount () {
    const render = this.render

    const initialRender = (...args) => {
      let result
      this.signal = observe(() => {
        if (this.render === initialRender) {
          result = render.apply(this, args)
        } else {
          this.forceUpdate()
        }
      })

      this.render = render
      return result
    }

    this.render = initialRender
  }

  componentWillUnmount () {
    this.signal.unobserve()
  }

}