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JsonDiffPatch

JsonDiffPatch is a library that allows for the diffing and patching of JSON objects.

npm install json-diff-patch-v2

Import JsonDiffPatch in your project:

import { DiffPatcher } from 'json-diff-patch-v2';

Create a DiffPatcher instance:

const diffPatcher = new DiffPatcher();

Use the diff, patch, and reverse methods to work with your JSON objects:

Diff: To find the difference between two objects.
Patch: To apply a patch to an object.
Reverse: To reverse a patch.

Examples

Diffing Two Objects

const left = { name: 'John', age: 25 };
const right = { name: 'John', age: 26 };

const delta = diffPatcher.diff(left, right);
console.log(delta);
// Output: { age: [25, 26] }

Patching an Object

const original = { name: 'John', age: 25 };
const delta = { age: [25, 26] };

const patched = diffPatcher.patch(original, delta);
console.log(patched);
// Output: { name: 'John', age: 26 }

Using Property Filter

In scenarios where you want to ignore certain properties during diffing, you can use the propertyFilter option.

const options = {
  propertyFilter: function(name) {
    return name.slice(0, 1) !== '$';
  },
};
const diffPatcherWithFilter = new DiffPatcher(options);

const left = { data: { $volatile: 123, stable: 456 } };
const right = { data: { $volatile: 124, stable: 456 } };

const delta = diffPatcherWithFilter.diff(left, right);
console.log(delta);
// Output: undefined (since the change is in a filtered property)