将两个javascript对象合并为一个?[副本]

var x =  {posts: 2};
var y = {notes: 1};
var z = Object.assign( {}, x, y );
console.log(z);

const posts = {  '2018-05-11': {    posts: 2  },  '2018-05-12': {    posts: 5  }};
const notes = {  '2018-05-11': {    notes: 1  },  '2018-05-12': {    notes: 3  }};

function objCombine(obj, variable) {
  for (let key of Object.keys(obj)) {
    if (!variable[key]) variable[key] = {};

    for (let innerKey of Object.keys(obj[key]))
      variable[key][innerKey] = obj[key][innerKey];
  }
}

let combined = {};
objCombine(posts, combined);
objCombine(notes, combined);
console.log(combined)

var posts = {'2018-05-11' : {posts: 2}} // var posts
var notes = {'2018-05-11' : {notes: 1}} // var notes

Object.assign(posts['2018-05-11'], notes['2018-05-11']);
console.log(posts);

const posts = {'2018-05-11' : {posts: 2}}
const notes = {'2018-05-11' : {notes: 1}}

const result = _.merge({}, posts, notes);
console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.js"></script>

var a =  {"2018-05-11" : {notes: 1}};

var b =  {"2018-05-11" : {posts: 3}};

var result = {};

Object.keys(a).forEach(k=>{result[k] = Object.assign(a[k],b[k])});

console.log(result);