No ES6 support?

[ryancheung]

Error on compile js with es6 syntax, like let ERRORMSG = {}:

V8::Error: Unexpected token: name (ERRORMSG)1

[ignisf]

Hello,

No, I don't think v8 3.16 provides ES6 support. Unfortunately TRR does not support newer versions of the V8 library.

This depends on #348