Sup

index.js

import * as React from 'react'

class Button extends React.PureComponent {
  render() {
    return (
      <button onClick={this.props.onClick}>{this.props.text}</button>
    }
  }
}

export default class extends React.PureComponent {
  state = {
    value: ''
  }
  
  onChange = (event) => {
    this.setState({
      [event.target.name]: event.target.value
    })
  }
  
  handleClick = () => {
    console.log(this.state.value)
  }

  render() {
    return [
      <input 
        key="0"
        name="value"
        type="text"
        value={this.state.value}
        onChange={this.handleChange}
      />,
      <Button onClick={this.handleClick} text="Submit" />
    ]
  }
}