Lets assume we want to have type representing two elements array in typescript.
Its simpe

type twoElementsArray = number[] & { length : 2}; 

Now lets try same trick with Set

type twoElementsSet = Set & {size : 2} 

const setOfTwo: twoElementsSet = new Set([1,2])

Now we have an error Type 'number' is not assignable to type '2'
Which looks a bit awkward. What is also worth noting while
trick with array works here

const arrayOfTwo : twoElementsArray = [1,2] 

It doesn’t here

const anotherArrayOfTwo: twoElementsArray = new Array(1,2); 

Do you have idea how one can enforce consistent behaviour so no matter how Array is constructed it can control number of elements on type level as well as Array/Set/Map whatever data structure symmetry ?