https://github.com/quentinroy/tiny-merge-patch
An FP-ready implementation of the JSON Merge Patch RFC 7396
https://github.com/quentinroy/tiny-merge-patch
7396 json merge patch rfc
Last synced: 25 days ago
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An FP-ready implementation of the JSON Merge Patch RFC 7396
- Host: GitHub
- URL: https://github.com/quentinroy/tiny-merge-patch
- Owner: QuentinRoy
- License: other
- Created: 2017-10-05T10:58:39.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2025-04-21T19:13:56.000Z (27 days ago)
- Last Synced: 2025-04-21T20:28:23.622Z (27 days ago)
- Topics: 7396, json, merge, patch, rfc
- Language: JavaScript
- Homepage:
- Size: 402 KB
- Stars: 4
- Watchers: 2
- Forks: 1
- Open Issues: 26
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
Tiny Merge Patch
================
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[](https://www.npmjs.com/package/tiny-merge-patch)
An implementation of the JSON Merge Patch
[RFC 7396](http://tools.ietf.org/html/rfc7396): a standard format used to
describe modifications to JSON documents.
This library complies with the functional programming style: it does not mutate
the original target, but recycles what it can. It is particularly appropriate to update a state used by [React](https://reactjs.org), allowing selective re-rendering of the UI.
`tiny-merge-patch` passes all [RFC 7396](http://tools.ietf.org/html/rfc7396) tests.
## Install
Install the current version (and save it as a dependency):
### npm
```sh
npm install tiny-merge-patch --save
```
## Import
### CommonJs with node
```js
// Fetch `apply` from the module.
const mergePatch = require('tiny-merge-patch').apply;
```
### ES modules in the browser
```js
// `apply` is also the default export.
import mergePatch from 'https://unpkg.com/tiny-merge-patch/esm/index.js'
```
## Usage
```js
// Original document / object.
const doc = {
a: 'b',
c: { d: 'e', f: 'g' },
h: { i: 0 }
};
// JSON merge patch to apply.
const patch = {
a: 'z',
c: { f: null } // null marks deletions.
};
// Apply the patch.
const patchedDoc = mergePatch(doc, patch);
// tiny-merge-patch complies with the RFC specification.
assert.deepEqual(patchedDoc, {
a: 'z',
c: { d: 'e' },
h: { i: 0 },
});
// Additionally, it does not mutate the original document...
assert(patchedDoc !== doc);
// ...nor its content...
assert(patchedDoc.c !== doc.c);
// ...but recycles what it can.
assert(patchedDoc.h === doc.h);
```
## Alternatives
- [`json-merge-patch`](https://github.com/pierreinglebert/json-merge-patch) (from which this library is forked)
- [`merge-patch`](https://github.com/krisnye/merge-patch)
- [`json8-merge-patch`](https://github.com/JSON8/merge-patch)
All are in-place.
To avoid mutations of the original object, one can deep-clone beforehand, but it can be expensive.
At the contrary, `tiny-merge-patch` does not alter any of its arguments—but
recycles what it can.
Recycling also allows efficient strict identity-based memoization
(used by [React](https://reactjs.org)'s [PureComponent](https://reactjs.org/docs/react-api.html#reactpurecomponent) for example).
All of the above libraries also embed additional functionalities, such as patch generation from two objects or merge of patches.
`tiny-merge-patch` only focuses on the IETF standard and on patch applications.
(None of the above libraries are particularly big.
Still, `tiny-merge-patch` is smaller if you only need to apply patches.
It is also worth mentioning that unlike
[JSON patches](https://tools.ietf.org/html/rfc6902), there is no way to
implement merge of merge patches that reliably preserves deletion.)
- [`immutable-merge-patch`](https://www.npmjs.com/package/immutable-merge-patch): JSON merge patch implementation for [Immutable.js](https://facebook.github.io/immutable-js/).
# License
[MIT](./LICENSE)