Again, without a sample project it’s hard to tell for sure. One thing that come to mind is the functions are declared as arrow functions, at least from the code you‘re posting. IE 10 and 11 are not supporting arrow functions. Sadly the color-convert GitHub Page says nothing on supported browsers. And at least from the webpack configs I’ve seen, node_modules dependencies are usually excluded from Babel to transpile it to ES5.
Regarding webpack 2 and resolve I’m not sure what you mean. Do you speak of the resolve part in the webpack config? Also here would a full webpack config, you’re using, helpful.
Edit: I looked into the color-convert code (from my cell) and there are no arrow functions in the code, so no idea how they are ending up in your bundle.
Sebastian
Whats the error message in the console? What tools you use to build the app?
My last rumble with IE was that react is using the Symbol datatype and therefor the babel polyfill had to load at first on order to work in IE. But it was React 16 in my case.