JSON8 Merge Patch

Introduction

JSON Merge Patch RFC 7396 toolkit for JavaScript.

• Introduction
• Getting started
• Methods
  • apply
  • patch
  • diff

Getting started

npm install json8-merge-patch

const mergePatch = require("json8-merge-patch");

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Methods

apply

Apply a JSON Merge Patch to a JSON document.

• May mutates the target document, if you wish to pass a shallow copy use JSON8 clone.
• Does not validate the patch nor the target nor the result for JSON correctness, use JSON8 valid.

doc = mergePatch.apply(doc, mergePatch);

let person = {
  "name": "John Doe",
  "friendly": true,
  "age": 18,
  "address": {
    "country": "France"
  }
}

const patch = {
  "age": 19,
  "friendly": "maybe"
  "address": {
    "country": null
  }
}

person = mergePatch.apply(person, patch)
/*
{
  "name": "John Doe",
  "friendly": "maybe",
  "age": 19,
  "address": {}
}
*/

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object creation

When needed, apply creates objects with null prototype, you can choose the prototype to use with {proto: Object} as a third argument.

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prototype pollution

apply will throw with an error if prototype pollution is attempted. You can allow for prototype pollution by passing {pollute: true} as a third argument.

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patch

Alias for apply method.

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diff

Compares two JSON documents and returns a JSON Merge Patch.

const a = { foo: "bar", bar: "foo" };
const b = { foo: "foo" };

mergePatch.diff(a, b);
/*
{
  "foo": "foo",
  "bar": null
}
*/

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