Convert array into nested object

Question

Let's say I have the following array: ['product' , 'model', 'version']

And I would like to have an object such as:

{
    product: { 
        model: { 
            version: { 

            }
        }
     }
}

However, that array is dynamic so it could have 2, 3 or fewer more items. How can this be achieved in the most efficient way?

Thanks

Rule

Do you need to create just exactly this empty object? Or do you need to merge those keys into an existing objects also containing other keys? – Counterclaim

It can be anything in the value for now as I got access to the data I need to add to this object, but it needs to be within this structure. Tks – Rule

Answer 1

Just turn it inside out and successively wrap an inner object into an outer object:

const keys = ['product', 'model', 'version'];
const result = keys.reverse().reduce((res, key) => ({[key]: res}), {});
//                                   innermost value to start with ^^

console.log(result);

Counterclaim

{[key]: res} --- has this always been a thing? [key]:value ? – Airtight

Not always. Computed keys exist since ES2016 or so. – Counterclaim

Bear in mind that keys.reverse will mutate the original array. Using keys.reduceRight (as suggested below) may be preferable. – Spurt

If you want the final "leaf" of your object tree to contain a value other than an empty object, you can use a ternary keys.reduceRight((res, key, i) => (i === keys.length - 1 ? {[key]: myValue} : {[key]: res}) , {}); – Abixah

Answer 2

You can also do it with Array.prototype.reduceRight:

const result = ['product','model','version'].reduceRight((all, item) => ({[item]: all}), {});

console.log(result);

Conners

Answer 3

If I understood request correctly, this code might do what you need:

function convert(namesArray) {
  let result = {};
  let nestedObj = result;
  namesArray.forEach(name => {
    nestedObj[name] = {};
    nestedObj = nestedObj[name];
  });

  return result;
}


console.log(convert(['a', 'b', 'c']));

Outguard

Worked as expected !! Thanks for your help!! – Rule

Answer 4

function convert(namesArray, val) {
  let result = {};
  let nestedObj = result;
  namesArray.forEach((name, index) => {
    nestedObj[name] = index === namesArray.length - 1 ? val : {};
    
    nestedObj = nestedObj[name];
  });

  return result;
}
console.log(convert(["a", "b", "c"], 3));

Intromission