ES6 support

[marie-j]

Is your feature request related to a problem? Please describe. Currently when trying to write Javascript expression due to Otto limitation we are obliged to use only ES5 features. This can be painful as we have to rewrite existing functions in some cases (Example: we have to use a for loop instead of using Array.prototype.find)

Describe the solution you'd like Be able to write Javascript expression using ES6 features

Describe alternatives you've considered For instance: https://github.com/dop251/goja

Additional context