String.prototype.includes not converted to ES5

Question

ES6's String.prototype.includes function is left as is when compiling to ES5 (CLI babel 5.0.9)

Sorry if this a FAQ, I did search thoroughly.

Answer 1

Babel converts ES6 syntax into ES5 syntax. It is up to you to load a polyfill so that new ES6 library functions are available. Generally you'd do this with

import 'babel/polyfill';