I just installed gsap 2.0.1 and transpile the gsap modules with babel via Webpack now and it works fine. For people still having this issue, maybe this helps.   This is what I changed in the webpack config: Instead of excluding the node_modules folder for the babel-loader, I now replace the exclude rule by an include-rule including both my source-folder as well as the gsap folder inside node_modules, like this: (change your sourcepath in case you're not working with src or ha