Simple sample works as expected:

type Data = {
    a: number
    b: number
}

const data: Data[] = [
    {a :1, b: 1},
    {a: 2, b: 2}
].sort((el1, el2) => el1.a - el2.a)

sorting works, type is preserved.

But it does not work to array of tuples:

type Data = [number, number]

const data: Data[] = [ // error: Type number[][] is not assignable to type Data[]
    [1, 2],
    [3, 4]
].sort((a, b) => a[0] - b[0])

And with heterogeneous items it’s even more crazy:

type Data = [number, number]

const data: Data[] = [ // error: Type '(number | boolean)[][]' is not assignable to type 'Data[]'
    [1, true],
    [3, false]
].sort((a, b) => a[0] - b[0])
//      ^? (parameter) a: (number | boolean)[]

Are my types conceptually wrong? Or is it a known limitation and, if yes, is there a workaround?

PS I know .sort() mutates an array. But since top-level is not a tuple, I’d expect Typescript preserve result type and properly infer element’s type inside of .sort()