Why is targeting es5 6x faster than es6

[winksaville]

See Change to target: es5 instead of es6.

[winksaville]

Here is somebody that found classes were slow.

[winksaville]

So it appears the problem is that v8 5.8 may just be slower when targeting es6. I add a comment to node js PR 13515. So when that PR lands I'll give it a try and see if it resolves the performance issue.