Runtime error of Object.assign

[Khachatour]

Hey there folks!!
I am using this great tool, in our pretty big react application. So we have our own error reporter for runtime error, and yesterday I've noticed Object.assign is not a function, after debugging trough our minified code, we finally found where it was. In ./src/createProps.js on line 9. Yes and by the way the browser from which we got that error was very old, if I im not wrong it was Firefox 32 or something. So the problem is that Object.assign is not supported there. And there is no check for support and usage of polyfill.
So thats the info about error. It would be very cool and pleasing to me, if you allow me to fix this and give you a pr :)

[jacargentina]

@Khachatour please test with https://jacargentina.github.io/react-flexbox-grid/. It includes @babel/polyfill si it should work fine.