There is a code snippet showcasing a recursive function designed to take a number, for example n=5, and produce an array counting down from n to 1 (i.e., [5,4,3,2,1]).
The point of confusion arises just before the numbers/values of n are added to countArray. The query centers around how countup(n - 1) generates the sequence of numbers like 5, 4, 3, 2, 1. It seems puzzling where or how these values get stored. One might expect n to simply become its last defined value, such as n=1, or result in a blank array. However, the reality is that all these values get added into an array that seemingly comes out of nowhere, without prior definition. This is what needs clarification regarding those two lines with comments.
tl;dr: (1) How are the values 5 through 1 saved without getting overwritten by the final value of 1 before being pushed into the array? (2) When and how was countArray actually established as an array before we start adding elements to it?
function countup(n) {
if (n < 1) {
return [];
} else {
const countArray = countup(n - 1); //The storage logic behind 5, 4, 3, 2, 1 utterly confuses me
countArray.push(n); //I'm perplexed about when countArray became initialized as an array
return countArray;
}
}
console.log(countup(5)); // [ 1, 2, 3, 4, 5 ]
Edit: Perhaps this post's title should focus more on arrays than variables or similar topics.