How to change key name with map into nested object?

Question

Here is the object

{
  a: 1,
  b: {
   c: {
     d: 2
   },
   e: 3
  }
}

Here is the map

{
  'a': 'aaa',
  'b': 'bbb',
  'b.c.d': 'bcd'
}

Here is the expected result.

{
  aaa: 1,
  bbb: {
   c: {
     bcd: 2
   },
   e: 3
  }
}

I know there's a function in lodash _.get could get the value like b.c.d.
But how can I change the key name with the map?

Answer 1

You can do this recursively by keeping track of the current path and building a key into the map with that:

let o = {a: 1,b: {c: {d: 2},e: 3}}
let map =  {
    'a': 'aaa',
    'b': 'bbb',
    'b.c.d': 'bcd'
}

function makeObj(obj, map, p=[]) {
    let ret = {}
    Object.entries(obj).forEach(([k, v]) => {
        let path = p.concat(k)                  // add onto current path
        let mapKey = map[path.join('.')] || k
        
        ret[mapKey] = (typeof v === 'object')
            ? makeObj(v, map, path)             // if an object recurse and pass on the current path  
            : v                                 // otherwise set the value
    })
    return ret
}

console.log(makeObj(o, map))