import Only from 'react-only-when'
<Only when={true}>
  <h1>Here I Am</h1>
</Only>

import React from 'react';
import Only from 'react-only-when'
class App extends React.Component {
  state = {
    show: true
  };
  toggle = () => this.setState(state => ({ show: !state.show }));
  render() {
    const { show } = this.state;
    return (
      <div className="app">
        <button onClick={this.toggle}>Toggle</button>
        <Only when={show}>
          <h1>Here I Am</h1>
        </Only>
      </div>
    );
  }
}