Could this be an `Object.keys()` option?

[eemeli]

Rather than introducing a new method, could the proposal instead be about adding a second argument to Object.keys()? As in:

const a = [13, 42]
a.foo = 99

Object.keys(a) // [ '0', '1', 'foo' ]
Object.keys(a, { numeric: true }) // [ '0', '1' ]
Object.keys(a, { numeric: false }) // [ 'foo' ]

[ljharb]

I like the cleanliness of that, but we heard a lot of pushback from committee yesterday about avoiding options bags in performance-motivated proposals.

[eemeli]

But isn't this more of a correctness and ergonomics -focused proposal, rather than one that's about performance?

[ljharb]

This should be much much faster overall and easier to follow in code

from the readme