Expose jQuery $ in the window so it can be accessed by jQuery plugins

theme.js

// In the root directory of the theme, install your plugin:
//
// > yarn add jquery-zoom
//
// Add the line below to the top of scripts/layout/theme.js

import $ from 'jquery';

// Below your imports, set up jQuery so that it can be accessed
// from the HTML
window.jQuery = $;
window.$ = $;

// Finally, require the plugin
require('jquery-zoom');