just-diff-apply

What is just-diff-apply?

The npm package 'just-diff-apply' is a utility that allows users to apply differences between objects or arrays. It is typically used in scenarios where changes need to be tracked and applied, such as in state management or data synchronization.

What are just-diff-apply's main functionalities?

Applying differences to objects

This feature allows you to apply a set of differences to an object. In the provided code, a difference is applied to change the value of 'a' from 3 to 4.

const diffApply = require('just-diff-apply');
const obj = {a: 3, b: 5};
const diff = [{op: 'replace', path: ['a'], value: 4}];
diffApply(obj, diff);
console.log(obj); // {a: 4, b: 5}

Applying differences to arrays

This feature enables the application of differences to arrays. In the example, an element with value 5 is added at index 1.

const diffApply = require('just-diff-apply');
const arr = [1, 2, 3];
const diff = [{op: 'add', path: [1], value: 5}];
diffApply(arr, diff);
console.log(arr); // [1, 5, 2, 3]

Other packages similar to just-diff-apply

jsondiffpatch

jsondiffpatch is a library for diffing and patching JSON-structured data. It offers more complex diffing strategies and can handle larger and more complex data structures compared to just-diff-apply.

deep-diff

deep-diff is another npm package that provides a way to observe differences between objects and arrays and apply changes. It is similar to just-diff-apply but also includes functions for reverting changes and detailed tracking of changes.

README

just-diff-apply

Part of a library of zero-dependency npm modules that do just do one thing. Guilt-free utilities for every occasion.

🍦 Try it

npm install just-diff-apply

yarn add just-diff-apply

Apply a diff object to an object. Pass converter to apply a http://jsonpatch.com standard patch

  import {diffApply} from 'just-diff-apply';

  const obj1 = {a: 3, b: 5};
  diffApply(obj1,
    [
      { "op": "remove", "path": ['b'] },
      { "op": "replace", "path": ['a'], "value": 4 },
      { "op": "add", "path": ['c'], "value": 5 }
    ]
  );
  obj1; // {a: 4, c: 5}

  const obj2 = {a: 3, b: 5};
  diffApply(obj2,
    [
      { "op": "move", "from": ['a'], "path": ['c']},
    ]
  );
  obj2; // {b: 5, c: 3}

  // using converter to apply jsPatch standard paths
  // see http://jsonpatch.com
  import {diffApply, jsonPatchPathConverter} from 'just-diff-apply'
  const obj3 = {a: 3, b: 5};
  diffApply(obj3, [
    { "op": "remove", "path": '/b' },
    { "op": "replace", "path": '/a', "value": 4 }
    { "op": "add", "path": '/c', "value": 5 }
  ], jsonPatchPathConverter);
  obj3; // {a: 4, c: 5}

  // arrays (array key can be string or numeric)
  const obj4 = {a: 4, b: [1, 2, 3]};
  diffApply(obj4, [
    { "op": "replace", "path": ['a'], "value": 3 }
    { "op": "replace", "path": ['b', 2], "value": 4 }
    { "op": "add", "path": ['b', 3], "value": 9 }
  ]);
  obj4; // {a: 3, b: [1, 2, 4, 9]}

  // nested paths
  const obj5 = {a: 4, b: {c: 3}};
  diffApply(obj5, [
    { "op": "replace", "path": ['a'], "value": 5 }
    { "op": "remove", "path": ['b', 'c']}
    { "op": "add", "path": ['b', 'd'], "value": 4 }
  ]);
  obj5; // {a: 5, b: {d: 4}}