With v4, angular starts to ship ES6 code as part of its npm packages. However, Angular's compiler has no option to output ES6 code, only TypeScript code (for AOT) or ES5 code (for JIT).
Also, our metadata collection is broken for JIT and native ES6 mode (see #15325).
Add an option to allow to use ES6 in both cases.
With v4, angular starts to ship ES6 code as part of its npm packages. However, Angular's compiler has no option to output ES6 code, only TypeScript code (for AOT) or ES5 code (for JIT).
Also, our metadata collection is broken for JIT and native ES6 mode (see #15325).
Add an option to allow to use ES6 in both cases.