Creating a new object that's a combination of others object

combining-objects.js

// Creating a new object that's a combination of
// `state` and `changes` objects.
// Old JavaScript:
var newState = {};

[state, changes].forEach(function(obj) {
  for (var propName in obj) {
    if (obj.hasOwnProperty(propName)) {
      newState[propName] = obj[propName];
    }
  }
});

// Modern JavaScript
const newState = { ...state, ...changes };