One caveat off the top of my head: check the bundle that is being served to search crawlers can be interpreted correctly. For Google Search, our web rendering service is based on Chrome 41.
I would just check to ensure the legacy (non-ES2015) bundle doesn't also contain anything that requires additional polyfills. If it does, look at ways you can feature detect and serve that additional JS as needed.
One caveat off the top of my head: check the bundle that is being served to search crawlers can be interpreted correctly. For Google Search, our web rendering service is based on Chrome 41.
I would just check to ensure the legacy (non-ES2015) bundle doesn't also contain anything that requires additional polyfills. If it does, look at ways you can feature detect and serve that additional JS as needed.
Hadn’t thought of crawlers! Great shout, thank you.