# App Launch Error

**URL:** <https://forum.webostv.developer.lge.com/t/app-launch-error/3020>\
**Category:** Web App Development\
**Created:** [May 25, 2023, 6:05am UTC](https://forum.webostv.developer.lge.com/t/app-launch-error/3020 "2023-05-25T06:05:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![user401](https://avatars.discourse-cdn.com/v4/letter/u/258eb7/32.png) [@user401](https://forum.webostv.developer.lge.com/u/user401)\
**Post date:** [May 25, 2023, 6:05am UTC](https://forum.webostv.developer.lge.com/t/app-launch-error/3020/1 "2023-05-25T06:05:48Z")

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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

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**Author:** ![narae0.kim](https://avatars.discourse-cdn.com/v4/letter/n/87869e/32.png) [@narae0.kim](https://forum.webostv.developer.lge.com/u/narae0.kim)\
**Post date:** [May 25, 2023, 7:17am UTC](https://forum.webostv.developer.lge.com/t/app-launch-error/3020/2 "2023-05-25T07:17:57Z")

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The webOS TV uses different web engines depending on the webOS version. (See [Web API and Web Engine](https://webostv.developer.lge.com/develop/specifications/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.