App Launch Error

I have developed ReactJS app with ES6 JS features. App works perfectly fine in WebOS 6.X and 7.X, but when i tried launching the same on WebOS 4.x and 5.x it failed with many JS errors.

I am using babel to transpile the code for older browsers as well. Please suggest how should i proceed

The webOS TV uses different web engines depending on the webOS version. (See Web API and Web Engine.) So please check the scope of support for the web API that you want to use based on the web engine information first. Thank you.