TS Tuple - manage a defined collection of tuples

tuple.ts

interface FixedArray<Size extends number, A> extends ArrayLike<A> { length: Size }

type MyTriple = FixedArray<3,number>

const ok_case: MyTriple = [1,2,3] as const // ok !
const erro_case1: MyTriple = [1,2] as const // fewer elements
const erro_case2: MyTriple = [1,2,3,4] as const // many elements
const erro_case3: MyTriple = [1,2,3] // not constant in static-time
const erro_case4: MyTriple = [] as const // well, it's empty my son!

const f = <A extends FixedArray<1|2|3, B>,B>(n_tuple: A) => {
    const size = n_tuple.length
    switch (size) {
        case 1: break;
        case 2: break;
        case 3: break;
    }
}

f(['X'] as const)
f(['X',0] as const)
f(['X',0,0] as const)
f(['X',0,0,1] as const) // Type '4' is not assignable to type '1 | 2 | 3'.ts(2345)

Note: define MyTriple as below has the same effect, with the benefit of the sintax sugar of not being required to use the termination 'as const' when assign a tuple instance:

type MyTriple_ = readonly [number] | readonly [number, number] | readonly [number, number, number]