How to make a nested object out of an array

Question

given an array like [‘a’, ‘b’, ‘c’]

how can i get an object like

{
 current: ‘a’,
 next : { 
 current: ‘b’,
 next: {
 current: ‘c’
 }
 }
}

Answer 1

You can make a recursive function for this:

const data = ['a', 'b', 'c'];
function createObj([current, ...rest]) {
 const result = { current };
 if (rest.length) result.next = createObj(rest);
 return result;
}
console.log(createObj(data));

The [current, ...rest] is a single destructured array argument.

• RenaissanceProgrammer: i ended up using this answer as it also translates to other languages easily

Answer 2

You can use Array.reduceRight() to create the object:

const arr = ['a', 'b', 'c']
const obj = arr.reduceRight((acc, o) => ({
 current: o,
 ...acc && { next: acc }
}), null)
console.log(obj)

• RenaissanceProgrammer: both answers are good, i’m not sure which to select
• Ori Drori: lol. Try them both for your use case, and see which is more readable, and works better for you.