function that receive an object and change the values by the type of the key

getTypes.js

var o = {
  '1': 'adios',
  '2': 1.5,
  '3': true,
  '4': [1, 2, 3],
  '5': {1: 2}
}

const getTypes = obj => {
  return Object.keys(obj).reduce((prev, key) => {
    prev[key] = Array.isArray(obj[key]) ? 'array' : typeof obj[key]
    return prev
  }, {})
}

console.log(getTypes(o))

// { '1': 'string',
//   '2': 'number',
//   '3': 'boolean',
//   '4': 'array',
//   '5': 'object' }