I have a fresh created Angular 4 CLI app. After running this:
npm install bootstrap@4.0.0-beta jquery popper.js --save
and editing .angular
Include popper.js before bootstrap.js:
popper.js
bootstrap.js
"scripts": [ "node_modules/jquery/dist/jquery.slim.min.js", "node_modules/popper.js/dist/umd/popper.min.js", "node_modules/bootstrap/dist/js/bootstrap.min.js" ],