How to create Object with nested Objects from an Array

Question

I have an array [1, 2, 3] and I want to transfer it to object with nested parent-child objects's series like this :

{ value: 1, rest: { value: 2, rest: { value: 3, rest: null } } 

If I have an array [1, 2, 3, 4] the result will be like this :

{ value: 1, rest: { value: 2, rest: { value: 3, rest: { value:4, rest:null } } 

The best effort of me is this snippet of code :

const arrayToList = (array) => {
  let list = { value: null, rest: null };
  for (let e of array) {
    array.indexOf(e) === 0 && (list.value = e);
    array.indexOf(e) >= 1 && (list.rest = { value: e });
  }
  return list;
};
console.log(arrayToList([1, 2, 3]));

Answer 1

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);