The following features are not yet implemented, but can be implemented safely:

• get Array[@@species]

• get Map[@@species]

• get Set[@@species]

• Math.imul(), Math.clz32(), Math.fround(), Math.log10(), Math.log2(), Math.log1p(), Math.expm1(), Math.cosh(), Math.sinh(), Math.tanh(), Math.acosh(), Math.asinh(), Math.atanh(), Math.hypot(), Math.trunc(), Math.sign(), Math.cbrt()

• generic Date.prototype.toString(), Date.prototype[@@toPrimitive]

• Proxy

• Reflect

• generic RegExp.prototype.toString(), RegExp.prototype[@@match](), RegExp.prototype[@@replace](), RegExp.prototype[@@search](), RegExp.prototype[@@split](), get RegExp[@@species]

• String.prototype.normalize(), String.raw()

• Symbol.match, Symbol.species, Symbol.toPrimitive, Symbol.prototype[@@toPrimitive], Symbol.replace, Symbol.search, Symbol.split, Symbol.unscopables

• Typed Arrays (Can't be implemented efficiently due to ArrayBuffer)

• arguments[@@iterator](By manually calling an ES6 utility method in function body)

• Template strings

• class (Manual class inheritance methods)

• @@StringTag can be added to Classes

• @@StringTag can be added to TypedArray