Modal using portal

Modalportal.js

import React from 'react';
import ReactDOM from 'react-dom';

import css from './Modal.css';

let modalRoot;

class Modal extends React.Component {
  constructor(props) {
    super(props);
    this.el = document.createElement('div');
  }

  componentDidMount() {
    modalRoot = document.getElementById('modal-root');
    modalRoot.appendChild(this.el);
  }

  componentWillUnmount() {
    modalRoot.removeChild(this.el);
  }

  render() {
    return ReactDOM.createPortal(
      <div className={css.Modal}>{this.props.children}</div>,
      this.el
    );
  }
}

export default Modal;