JSON-Patch

A leaner and meaner implementation of JSON-Patch. Small footprint. High performance. Also support dual directions! I.e. you can both apply patches and generate patches.

Why you should use JSON-Patch

JSON-Patch (RFC6902) is a new standard format that allows you to update a JSON document by sending the changes rather than the whole document. JSON Patch plays well with the HTTP PATCH verb (method) and REST style programming.

Mark Nottingham has a nice blog about it.

Footprint

0.5 KB minified and gzipped (1.1 KB minified)

Performance

Features

• Allows you to apply patches on object trees for incoming traffic.
• Allows you to freely manipulate object trees and then generate patches for outgoing traffic.
• ES6/7 Object.observe() is used when available.

Roadmap

• A /bin directory will be added with minified versions
• More unit tests

Adding to your project

In a web browser

Include json-patch.js if you want support for applying patches or include json-patch-duplex.js if you also want to generate patches.

In Node.js

Add fast-json-patch to dependencies list in your project's package.json, then run npm install. After installation, you are ready to go with require:

var jsonpatch = require('fast-json-patch')

Usage

Applying patches:

var myobj = { firstName:"Albert", contactDetails: { phoneNumbers: [ ] } };
var patches = [
   {op:"replace", path:"/firstName", value:"Joachim" },
   {op:"add", path:"/lastName", value:"Wester" },
   {op:"add", path:"/contactDetails/phoneNumbers/0", value:{ number:"555-123" }  }
   ];
jsonpatch.apply( myobj, patches );
// myobj == { firstName:"Joachim", lastName:"Wester", contactDetails:{ phoneNumbers[ {number:"555-123"} ] } };

Generating patches:

var myobj = { firstName:"Joachim", lastName:"Wester", contactDetails: { phoneNumbers: [ { number:"555-123" }] } };
observer = jsonpatch.observe( myobj );
myobj.firstName = "Albert";
myobj.contactDetails.phoneNumbers[0].number = "123";
myobj.contactDetails.phoneNumbers.push({number:"456"});
var patches = jsonpatch.generate(observer);
// patches  == [
//   { op:"replace", path="/firstName", value:"Albert"},
//   { op:"replace", path="/contactDetails/phoneNumbers/0/number", value:"123"},
//   { op:"add", path="/contactDetails/phoneNumbers/1", value:{number:"456"}}];

Testing

In a web browser

1. Testing json-patch.js

• Load src/patchtest.html in your web browser

2. Testing json-patch-duplex.js

• Load src/test-duplex.html in your web browser

Each of the test suite files contains Jasmine unit test suite and JSLitmus performance test suite.

To run JSLitmus performance tests, press "Run Tests" button.

In Node.js

1. Go to directory where you have cloned the repo
2. Install Jasmine Node.js module by running command npm install jasmine-node -g
3. Testing json-patch.js

• Run command jasmine-node --matchall --config duplex no src/test.js

4. Testing json-patch-duplex.js

• Run command jasmine-node --matchall --config duplex yes src/test.js src/test-duplex.js