https://github.com/ken107/jsonpatch-observe

Observe objects recursively for changes and generate JSON Patches
https://github.com/ken107/jsonpatch-observe

data-binding firebase harmony-proxies json json-patch json-rpc

Last synced: 19 days ago
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Observe objects recursively for changes and generate JSON Patches

• Host: GitHub
• URL: https://github.com/ken107/jsonpatch-observe
• Owner: ken107
• License: mit
• Created: 2015-06-30T18:05:34.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2024-06-19T02:09:50.000Z (5 months ago)
• Last Synced: 2024-10-12T05:13:24.078Z (about 1 month ago)
• Topics: data-binding, firebase, harmony-proxies, json, json-patch, json-rpc
• Language: TypeScript
• Homepage:
• Size: 717 KB
• Stars: 7
• Watchers: 3
• Forks: 0
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
Observe an object tree for changes and generate JSON Patches ([RFC 6902](https://tools.ietf.org/html/rfc6902)).  Uses [Harmony Proxy](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy), available in NodeJS version 6.4 and above.

### Usage

```javascript

const {observe} = require("jsonpatch-observe");

let observable = observe({});

observable.$subscribe(patch => console.log(patch));

observable.a = {b:1};		//prints {op:"add", path:"a", value:{b:1}}

observable.a.b = 2;		//prints {op:"add", path:"a/b", value:2}

delete observable.a;		//prints {op:"remove", path:"a"}

```

Note that the properties of an Observable are also Observables.  This is how it's able to detect when you do `observable.a.b = 2`.

### Unobserved Properties

You can exclude certain properties from `observe` as follows:

```javascript

require("jsonpatch-observe").config.excludeProperty = function(obj, prop) {

	//return true to exclude the property

}

```

### Splice Patch

The JSONPatch standard does not specify a "splice" operation.  Without splice, Array changes are represented as a series of individual "add", "replace", and "remove" operations, which can be quite inefficient to apply.

This module supports generating the splice patch.  Enable it as follows:

```javascript

require("jsonpatch-observe").config.enableSplice = true;

```

The splice patch has the following format:

```javascript

{

	op: "splice",

	path: "/myarr/3",		//path to array index

	remove: 2,			//number of elements removed

	add: ['a','b','c']		//elements added

}

```

I created a [fork](https://github.com/ken107/JSON-Patch) of Starcounter-Jack JSONPatch library capable of consuming this non-standard splice patch.