jsonMergePatch#

An implementation of the JSON Merge Patch RFC 7396.

JSON Merge Patch (RFC 7396) is a standard format that allows you to update a JSON document by sending the changes rather than the whole document. JSON Merge Patch plays well with the HTTP PATCH verb (method) and REST style programming.

There are three functions (merge, apply, and generate) for manipulating JSON objects. These functions are used for applying patches to JSON objects, merging JSON objects, and generating patches based on differences between JSON objects.

jsonMergePatch.merge#

Merges a patch JSON object into an original JSON object. If either the original or the patch is not a valid JSON object, it returns a deep clone of the patch.

Types#

• Json: Represents any valid JSON value.

Function Signature#

const merge: (original: Json, patch: Json) => Json

Parameters#

• original: The original JSON object to be merged.
• patch: The patch JSON object to merge into the original.

Return Value#

• Returns the Json object that is the merged result.

Usage#

import { jsonMergePatch } from 'jsoncargo';

const original = { a: 1, b: 2 };
const patch1 = { b: 3, c: 4 };
const patch2 = { a: null };

const result1 = jsonMergePatch.merge(original, patch1);
console.log(result1); // Output: { a: 1, b: 3, c: 4 }

const result2 = jsonMergePatch.merge(result1, patch2);
console.log(result2); // Output: { b: 3, c: 4 }

jsonMergePatch.apply#

Applies a patch to a target JSON object. If the patch or the target is not a valid JSON object, the target is replaced with a deep clone of the patch.

Types#

• Json: Represents any valid JSON value.

Function Signature#

const apply: (target: Json, patch: Json) => Json

Parameters#

• target: The target JSON object to which the patch will be applied.
• patch: The patch JSON object to apply to the target.

Return Value#

• Return the updated JSON object after applying the patch.

Usage#

import { jsonMergePatch } from 'jsoncargo';

const target = { a: 1, b: 2 };
const patch = { b: null, c: 3 };

const result = jsonMergePatch.apply(target, patch);

console.log(target); // Output: { a: 1, c: 3 }
console.log(result); // Output: { a: 1, c: 3 }
console.log(target === result); // Output: true

jsonMergePatch.generate#

Generates a patch JSON object that represents the differences between the original and result JSON objects. If either the original or the result is not a valid JSON object, it returns a deep clone of the result.

Types#

• Json: Represents any valid JSON value.

Function Signature#

const generate: (original: Json, result: Json) => Json

Parameters#

• original: The original JSON object.
• result: The resulting JSON object to compare with the original.

Return Value#

• Return the generated patch JSON object.

Usage#

import { jsonMergePatch } from 'jsoncargo';

const original = { a: 1, b: 2 };
const result = { a: 1, c: 3 };

const patch = jsonMergePatch.generate(original, result);

console.log(patch); // Output: { b: null, c: 3 }