es6 spread

babel-output.js

"use strict";

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

var state = {
  loggedIn: false
};

var newState = _extends({}, state, {
  loggedIn: "test"
});

state.loggedIn = true;

console.log(state);
console.log(newState);

es6-spread.js

const state = {
  loggedIn: false
};

const newState = {
  ...state,
  loggedIn: "test"
}

state.loggedIn = true;

console.log(state);
console.log(newState);