Consider move of some functions nested in Object namespace to global scope

[medikoo]

It should apply to those that relate to values in general (not necessary objects), e.g. string, number functions definitely.

e.g. ensureString, ensureNaturalNumber etc.

That way we would map native API, in sense that e.g. global isNaN accepts any non numeric value, while Number.isNaN confirms strictly on type of number NaN