Module not found: Error: Can't resolve 'core-js/es6'

Question

I\'ve got a problem with my build process in relation to my React app.

I always get the following error:

Module not found: Error: Can\'t resolve \'co

Answer 1

Sure, I had a similar issue and a simple

npm uninstall @babel/polyfill --save &&
npm install @babel/polyfill --save

did the trick for me.

However, usage of @babel/polyfill is deprecated (according to this comment) so only try this if you think you have older packages installed or if all else fails.