Just putting this out there so other’s don’t go through the same pain as we did. When upgrading our aurelia js SPA app to webpack 4, from requirejs, we noticed that an error with jQWidgets jqxcore lib not being able to find jquery to define jqxBaseFramework. To fix that you’ll want to use webpacks ProvidePlugin() method and load jquery globally as well as jqxBaseFramework. For example…
new ProvidePlugin({
Promise: 'bluebird',
$: 'jquery',
'window.$': 'jquery',
jQuery: 'jquery',
'window.jQuery': 'jquery',
jqxBaseFramework: 'jquery'
})