array.filter() should have an overload for type guards

[felixfbecker]

const a = [1, '2', 3]; // (number | string)[]
const b = a.filter(el => typeof el === 'number') // still (number | string)[], expected number[]

array.filter() should have an overload:

filter(predicate: (el: T, i, arr) => el is R): R[]

The same kind of overload is in rxjs' filter operator.

[RyanCavanaugh]

Please search. #7657

[felixfbecker]

mea culpa, I thought something seemingly simple as this would either be implemented already or not have an open issue.