fargo.jsx

import React, { Component }  from 'react'

class ManualStateComponent extends Component {
  state = {
    now: null
  }

  constructor(props) {
    super(props)
  }

  // Since you don't want to call `setState`, here is a method with the name you prefer
  rerender() {
    this.setState({
      now: Date.now()
    })
  }
}

// Example Component
class SimpleTimer extends ManualStateComponent {

  constructor(props) {
    super(props)
    
    this.seconds = 0 // Just a plain variable
  }

  componentDidMount() {
    setTimeout(() => {
      this.seconds++;
      this.rerender() // rerender!
    }, 1000)
  }
  
  render() {
    return <div>{this.seconds} secs have elapsed...</div>;
  }

}