Axel Rauschmayer (2015-04-11T02:29:56.000Z)
d at domenic.me (2015-04-19T23:38:18.590Z)
No engine has implemented subclassing of `Array`, yet: http://kangax.github.io/compat-table/es6/#Array_is_subclassable And, as Sebastian mentioned, you can’t transpile it, because it depends on the cooperation of `Array`: it becomes the base constructor and allocates an exotic array instance (with special handling for `length` etc.) whose prototype is `new.target`.