Serialize and apply patches from virtual-dom

Usage no npm install needed!

<script type="module">
  import vdomSerializedPatch from 'https://cdn.skypack.dev/vdom-serialized-patch';


vdom-serialized-patch Build Status Coverage Status

Serialize virtual-dom patches into a very efficient JSON format, and then patch the DOM directly from that object.

Designed for generating patches on the server or in a web worker and then sending that to the client. Basically this a more efficient and specialized version of vdom-as-json.


The virtual-dom library is great, but the problem is that the VirtualPatch object structure is:

  1. huge – containing the entire source node as well as the patch object and the object to be patched – and
  2. unserializable, since it uses custom classes like VirtualPatch and VirtualText.

This library solves both those problems, although to do so it has to implement its own version of virtual-dom/patch. So you'll have to use this library's patch method.


npm install vdom-serialized-patch


var h = require('virtual-dom/h');
var diff = require('virtual-dom/diff');
var serializePatch = require('vdom-serialized-patch/serialize');
var applyPatch = require('vdom-serialized-patch/patch');

var node1 = h('span', 'hello');
var node2 = h('span.heavy', {style: {'font-weight': 'bold'}}, 'hello world');

var patch = diff(node1, node2);
var serializedPatch = serializePatch(patch);

applyPatch(document.querySelector('#my-element'), serializedPatch);

In this case, the serialized patch will look like this:

  "0": [
        "style": {
          "font-weight": "bold"
        "className": "heavy"
        "p": {}
  "1": [
        "t": 1,
        "x": "hello world"
  "a": [

(This structure is not designed to be human-readable; it's designed to be efficient when doing JSON.stringify/JSON.parse).


This library, like vdom-as-json, doesn't support thunks or hooks or any of that stuff, because it's not possible to serialize custom behavior.

Testing this library

Test in node using JSDom:

npm test

Test in the browser using Zuul and PhantomJS:

npm run test-phantom

Test locally in your browser of choice:

npm run test-local

Test for code coverage:

npm run coverage