How to create Object with nested Objects from an Array

You can use reduceRight like so:

let obj = arr.reduceRight((rest, value) => ({ value, rest }), null);

It starts building the object from the inside out; it starts by creating the innermost object and then it uses that object as the rest property for the next outer object and so on until there are no more items in the array.

Demo:

let obj = [1, 2, 3, 4].reduceRight((rest, value) => ({ value, rest }), null);

console.log(obj);