Babel converts this to undefined

[jmzo]

is.js/is.js

Line 25 in 5629495

}(this, function() {

After webpack compiles, this line in the vendor.js file looks like })(undefined, function () { which crashes at page load at return root.is = factory() since root is undefined.

What happened to this, why did it become undefined literal?

[jmzo]

Adding this for reference in case it helps... https://stackoverflow.com/questions/34973442/how-to-stop-babel-from-transpiling-this-to-undefined