Example of how to merge the values of 2 objects in JavaScript

objectMergeES5.js

'use strict';

var _deepDiff = require('deep-diff');

var _objectAssignDeep = require('object-assign-deep');

var _objectAssignDeep2 = _interopRequireDefault(_objectAssignDeep);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var anyChanges = function anyChanges(newObject, originalObject) {
    return (0, _deepDiff.diff)(newObject, originalObject).length > 0;
};

var mergeChanges = function mergeChanges(newObject, originalObject) {
    return !anyChanges(newObject, originalObject) ? originalObject : (0, _objectAssignDeep2.default)(originalObject, newObject);
};

var london1801 = {
    innerLondon: 879491,
    outerLondon: 131666,
    greaterLondon: 1011157,
    country: 'England'
};

var london2001 = {
    innerLondon: 2765975,
    outerLondon: 4406061,
    greaterLondon: 7172036,
    country: 'England'
};

console.dir(mergeChanges(london2001, london1801));

objectMergeES6.js

import { diff } from 'deep-diff';
import objectAssignDeep from 'object-assign-deep';

const anyChanges = (newObject, originalObject) => {
    return diff(newObject, originalObject).length > 0;
};

const mergeChanges = (newObject, originalObject) => {
    return !anyChanges(newObject, originalObject) ? originalObject : objectAssignDeep(originalObject, newObject);
};

const london1801 = {
    innerLondon: 879491,
    outerLondon: 131666,
    greaterLondon: 1011157,
    country: 'England',
};

const london2001 = {
    innerLondon: 2765975,
    outerLondon: 4406061,
    greaterLondon: 7172036,
    country: 'England',
};

console.dir(mergeChanges(london2001, london1801));