# Yay. Just tried prepack and got 434kb Hello world!

**URL:** <https://discuss.kotlinlang.org/t/yay-just-tried-prepack-and-got-434kb-hello-world/2652>\
**Category:** JavaScript\
**Created:** [May 18, 2017, 9:35am UTC](https://discuss.kotlinlang.org/t/yay-just-tried-prepack-and-got-434kb-hello-world/2652 "2017-05-18T09:35:06Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Konstantin-Khvan](https://avatars.discourse-cdn.com/v4/letter/k/4af34b/32.png) [@Konstantin-Khvan](https://discuss.kotlinlang.org/u/Konstantin-Khvan)\
**Post date:** [May 18, 2017, 9:35am UTC](https://discuss.kotlinlang.org/t/yay-just-tried-prepack-and-got-434kb-hello-world/2652/1 "2017-05-18T09:35:06Z")

</div>

[https://prepack.io/](https://prepack.io/) actually works pretty good with kotlin.js stdlib  
My setup is manually concat kotlin.js + HelloWorld.js, use prepack on result and uglify prepack output. Got 434kb js file which actually outputs Hello World 😃  
With just uglify/webpack output is 608kb ~150% size