React 16: Portal

Portal.js

import React from "react";
import PropTypes from "prop-types";
import { createPortal } from "react-dom";

class Portal extends React.Component {
  static propTypes = {
    children: PropTypes.node,
  };

  state = { mounted: false };

  target = null;

  componentDidMount() {
    this.setState({ mounted: true });
  }

  componentWillUnmount() {
    if (this.target) {
      this.target.remove();
    }
  }

  getTarget() {
    if (!this.target) {
      this.target = document.createElement("div");
      document.body.appendChild(this.target);
    }
    return this.target;
  }

  render() {
    if (!this.state.mounted) {
      return null;
    }
    return createPortal(this.props.children, this.getTarget());
  }
}

export default Portal;