Ddiff NPM | npm.io

ddiff

Calculate differences between two data structures

Install

This project uses node and npm. Go check them out if you don't have them locally installed.

$ npm install --save ddiff

The UMD build is also available on jsdelivr:

<script src="https://cdn.jsdelivr.net/npm/ddiff/dist/ddiff.umd.js"></script>

You can find the library on window.ddiff.

Usage

import {diff} from 'ddiff';

const lhs = {
  name: 'my object',
  description: 'it\'s an object!',
  details: {
    it: 'has',
    an: 'array',
    with: ['a', 'few', 'elements']
  }
};

const rhs = {
  name: 'updated object',
  description: 'it\'s an object!',
  details: {
    it: 'has',
    an: 'array',
    with: ['a', 'few', 'more', 'elements', { than: 'before' }]
};

diff(lhs, rhs);
// [ { kind: 'E',
//     path: [ 'name' ],
//     lhs: 'my object',
//     rhs: 'updated object' },
//   { kind: 'A',
//     path: [ 'details', 'with' ],
//     index: 2,
//     item: { kind: 'E', path: [], lhs: 'elements', rhs: 'more' } },
//   { kind: 'A',
//     path: [ 'details', 'with' ],
//     index: 3,
//     item: { kind: 'N', rhs: 'elements' } },
//   { kind: 'A',
//     path: [ 'details', 'with' ],
//     index: 4,
//     item: { kind: 'N', rhs: { than: 'before' } } } ]

Changes

Change records have the following structure:

kind - indicates the kind of change; will be one of the following:
- N - indicates a newly added property/element
- D - indicates a property/element was deleted
- E - indicates a property/element was edited
- A - indicates a change occurred within an array
path - the property path (from the left-hand-side root)
lhs - the value on the left-hand-side of the comparison (undefined if kind === 'N')
rhs - the value on the right-hand-side of the comparison (undefined if kind === 'D')
index - when kind === 'A', indicates the array index where the change occurred
item - when kind === 'A', contains a nested change record indicating the change that occurred at the array index