[Solved]-react Portal - how to close modal when clicking outside of modal and how to assign ref to modal inside parent component rendering modal?-Reactjs

Since the click listener will be applied to all modal instances, I'd move the listener and the ref to a reuseable modal component -- now it'll control clicks once opened. The only thing it really needs is a passed down toggle modal function prop from the parent.

Working example:

components/Modal/index.js

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

class Modal extends PureComponent {
  componentDidMount() {
    document.addEventListener("click", this.closeModal, false);
  }

  componentWillUnmount() {
    document.removeEventListener("click", this.closeModal, false);
  }

  closeModal = ({ target }) => {
    if (this.modal && !this.modal.contains(target)) {
      this.props.toggleModal();
    }
  };

  render = () =>
    createPortal(
      <Fragment>
        <div className="overlay" />
        <div className="window-container">
          <div className="modal-container">
            <div ref={node => (this.modal = node)} className="modal">
              {this.props.children}
            </div>
          </div>
        </div>
      </Fragment>,
      document.body
    );
}

Modal.propTypes = {
  children: PropTypes.node.isRequired,
  toggleModal: PropTypes.func.isRequired
};

export default Modal;

components/Parent/index.js

import React, { Component } from "react";
import Modal from "../Modal";

class Parent extends Component {
  state = {
    showModal: false
  };

  toggleModal = () => {
    this.setState(prevState => ({
      showModal: !prevState.showModal
    }));
  };

  render = () => (
    <div className={`${this.state.showModal ? "blur" : undefined} app`}>
      <img
        src="https://i.imgur.com/BGwgr3A.jpg"
        className="image"
        alt="example.png"
        onClick={this.toggleModal}
      />
      {this.state.showModal && (
        <Modal toggleModal={this.toggleModal}>
          <h1 className="title">Hello!</h1>
          <p className="subtitle">There are two ways to close this modal</p>
          <ul>
            <li>Click outside of this modal in the grey overlay area.</li>
            <li>Click the close button below.</li>
          </ul>
          <button
            className="uk-button uk-button-danger uk-button-small"
            onClick={this.toggleModal}
          >
            Close
          </button>
        </Modal>
      )}
    </div>
  );
}

export default Parent;

styles.css

.app {
  text-align: center;
  margin-top: 20px;
}

.blur > img {
  -webkit-filter: blur(10px);
  -moz-filter: blur(10px);
  -ms-filter: blur(10px);
  -o-filter: blur(10px);
  filter: blur(10px);
}

.image {
  display: block;
  margin: 0 auto;
  cursor: pointer;
  width: 600px;
}

.modal {
  max-width: 600px;
  max-height: calc(100% - 96px);
  padding: 20px;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  position: relative;
  overflow-y: auto;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-shadow: 0px 11px 15px -7px rgba(0, 0, 0, 0.2),
    0px 24px 38px 3px rgba(0, 0, 0, 0.14), 0px 9px 46px 8px rgba(0, 0, 0, 0.12);
  box-shadow: 0px 11px 15px -7px rgba(0, 0, 0, 0.2),
    0px 24px 38px 3px rgba(0, 0, 0, 0.14), 0px 9px 46px 8px rgba(0, 0, 0, 0.12);
  border-radius: 4px;
  background-color: #fff;
  text-align: left;
}

.modal-container {
  opacity: 1;
  -webkit-transition: opacity 225ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;
  -o-transition: opacity 225ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;
  transition: opacity 225ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  height: 100%;
  outline: none;
}

.overlay {
  opacity: 1;
  -webkit-transition: opacity 225ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;
  -o-transition: opacity 225ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;
  transition: opacity 225ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: -1;
  position: fixed;
  -ms-touch-action: none;
  touch-action: none;
  background-color: rgba(0, 0, 0, 0.5);
  -webkit-tap-highlight-color: transparent;
}

.subtitle {
  margin: 0;
  text-align: center;
  font-weight: bold;
}

.title {
  text-align: center;
}

.window-container {
  text-align: center;
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  overflow: auto;
  outline: 0;
  -webkit-animation: fadeIn 0.2s 0s ease-in-out forwards;
  animation: fadeIn 0.2s 0s ease-in-out forwards;
  z-index: 100;
}