Creating a nested object from array of keys and target values

Question

I have and array of objects which I would like to transform into single js object. The array contains target value and array of keys. Note: I want this to work in vanilla js without importing scripts.

The source array:

[ 
  { value: 'res-1', keys: [ 'first' ] },
  { value: 'res-2', keys: [ 'second', 'deeperOne' ] },
  { value: 'res-3', keys: [ 'second', 'deeperTwo' ] },
  { value: 'res-4', keys: [ 'second', 'deeperThree', 'moreDeeper' ] },
  { value: 'res-5', keys: [ 'third' ]} 
 ]

Desirable result (object):

{
  first: 'res-1',
  second: {
    deeperOne: 'res-2',
    deeperTwo: 'res-3',
    deeperThree: {
      moreDeeper: 'res-4'
    }
  },
  third: 'res-5'
}

youmightnotneed.com/lodash#set might help. loop through array and use keys.join('.') to create path. — cmgchess
– cmgchess, Commented Jul 24, 2022 at 19:39
And there even is Plain js code. Please post this as answer, so I could give you some points! — Stūrainis
– Stūrainis, Commented Jul 24, 2022 at 19:50

Stūrainis · Accepted Answer · 2022-07-24 23:07:43Z

1

cmgchess gave answer to the question with a comment. Here is the code!

const array = [ 
  { value: 'res-1', keys: [ 'first' ] },
  { value: 'res-2', keys: [ 'second', 'deeperOne' ] },
  { value: 'res-3', keys: [ 'second', 'deeperTwo' ] },
  { value: 'res-4', keys: [ 'second', 'deeperThree', 'moreDeeper' ] },
  { value: 'res-5', keys: [ 'third' ]} 
 ]

const set = (obj, path, value) => {
  path.reduce((acc, key, i) => {
    if (acc[key] === undefined) acc[key] = {}
    if (i === path.length - 1) acc[key] = value
    return acc[key]
  }, obj)
}

let object = {}
array.forEach(({value, keys}) => set(object, keys, value))

console.log(object)

edited Jul 24, 2022 at 23:07

answered Jul 24, 2022 at 19:52

Stūrainis

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