As it's common arrays in js if you put 3 elements in array it will has length 3 but if I make array with only number two, it has length 2 ?!
const myArry=new Array(2)
console.log(myArry.length) // 2
new Array(2) means "make me an array with two empty slots". So yes, it has length 2.
You may be looking for const myArry = [2] which has length 1.
EDIT
Just for fun, if you really wanted to use constructor syntax instead of array literal syntax (the [2] part), you could do:
new Array(1).fill(2)
Which actually could make sense if both the length and the fill value were dynamic parameters.