Rerursive Object Tree Parser From String on VanillaJS

const strToObj = (arg) => {
  const arr = arg.push ? arg : arg.split('.')
  const obj = {}

  const _recursiveParsing = (arrBuff, objBuff) => {
    if (arrBuff.length === 0) {
      return obj
    }

    const keyToInsert = arrBuff[0]

    objBuff[keyToInsert] = arrBuff && arrBuff[1] ? {} : null

    return _recursiveParsing(arrBuff.slice(1, arr.length), objBuff[keyToInsert])
  }
 
  return _recursiveParsing(arr, obj)
}

const result = strToObj('a.b.c.d')

console.log(JSON.stringify(result))