Sage-9 + bootstrap popover + tether

Hi,
How to use bootstrap popover / How to import tether ? please
Here’s what I did in main.js :

import $ from 'jquery';
import Router from './util/router';

// Import Tether
import 'tether/dist/js/tether.js';

// Import Bootstrap
import 'bootstrap/dist/js/umd/util.js';
import 'bootstrap/dist/js/umd/alert.js';
import 'bootstrap/dist/js/umd/button.js';
import 'bootstrap/dist/js/umd/carousel.js';
import 'bootstrap/dist/js/umd/collapse.js';
import 'bootstrap/dist/js/umd/dropdown.js';
import 'bootstrap/dist/js/umd/modal.js';
import 'bootstrap/dist/js/umd/scrollspy.js';
import 'bootstrap/dist/js/umd/tab.js';
import 'bootstrap/dist/js/umd/tooltip.js';
import 'bootstrap/dist/js/umd/popover.js';

And in config.json :

"entry": {
"main": [
  "./scripts/main.js",
  "./scripts/front-page-popover.js",
  "./styles/main.scss"
], 

Here is the error message : Uncaught ReferenceError: Tether is not defined

thank you in advance

Are you using the latest Sage 9 ? https://github.com/roots/sage/tree/sage-9

Theter is provided to all scripts by webpack ProvidePlugin and is available without the need to import (same for jQuery):

https://github.com/roots/sage/blob/sage-9/webpack.config.js#L179

Yes, thank you, but i get the same error: tooltip.js:271 Uncaught ReferenceError: Tether is not defined