Bootstrap Dropdown not working in React

To make dropdown menu and other js stuff work in 4th Bootstrap you need just follow next steps:
install with npm to dependencies:

npm i --save bootstrap jquery popper.js

add it to index.js

import 'bootstrap';
import 'bootstrap/dist/css/bootstrap.css';
import 'bootstrap/dist/js/bootstrap.js';
import $ from 'jquery';
import Popper from 'popper.js';

all steps are taken from here