lodash - merge objects - build object based on array of strings

import * as _ from 'lodash';

const requestBody = {
  a: {
    a2: 10,
    c: {
      h1: 5,
    },
  },
  b: 2,
};
const fetchedFromDatabase = {
  a: {
    a2: 100,
    g: {
      f1: 10,
    },
    c: {
      h1: 50,
      h2: 10,
    },
  },
  b: 10,
};
let currentValues = {};
const updatedValues = {};
const flattenUpdatedFieldsSeparatedByDot = flattenObject(requestBody);

for (const separatedRequestField in flattenUpdatedFieldsSeparatedByDot) {
  const fetchedFromDatabaseValue = _.get(
    fetchedFromDatabase,
    separatedRequestField
  );
  currentValues = {
    ...currentValues,
  };
  _.set(currentValues, separatedRequestField.split('.'), fetchedFromDatabaseValue)
}

console.log(currentValues);
// now _.merge()

function flattenObject(value: any): Object {
  let toReturn: any = {};

  for (const i in value) {
    if (!value.hasOwnProperty(i)) {
      continue;
    }

    if (typeof value[i] == 'object') {
      const flatObject = flattenObject(value[i]);
      for (const x in flatObject) {
        if (!flatObject.hasOwnProperty(x)) continue;

        toReturn[i + '.' + x] = flatObject[x];
      }
    } else {
      toReturn[i] = value[i];
    }
  }
  return toReturn;
}