JSON Diff Kit

[![NPM version][npm-image]][npm-url]
[![Downloads][download-badge]][npm-url]

A better JSON differ & viewer library written in TypeScript. Try it out in the playground!

Install

You can install json-diff-kit via various package managers.

``sh


using npm

npm i json-diff-kit --save

using yarn

yarn add json-diff-kit

using pnpm

pnpm add json-diff-kit
`

Quick Start

To generate the diff data:

`ts
import { Differ } from 'json-diff-kit';
// or if you are using vue, you can import the differ only
import Differ from 'json-diff-kit/dist/differ';

// the two JS objects
const before = {
a: 1,
b: 2,
d: [1, 5, 4],
e: ['1', 2, { f: 3, g: null, h: [5], i: [] }, 9],
m: [],
q: 'JSON diff can\'t be possible',
r: 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.',
s: 1024,
};
const after = {
b: 2,
c: 3,
d: [1, 3, 4, 6],
e: ['1', 2, 3, { f: 4, g: false, i: [7, 8] }, 10],
j: { k: 11, l: 12 },
m: [
{ n: 1, o: 2 },
{ p: 3 },
],
q: 'JSON diff is possible!',
r: 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed quasi architecto beatae incididunt ut labore et dolore magna aliqua.',
s: '1024',
};

// all configs are optional
const differ = new Differ({
detectCircular: true, // default true
maxDepth: Infinity, // default Infinity
showModifications: true, // default true
arrayDiffMethod: 'lcs', // default "normal", but "lcs" may be more useful
});

// you may want to use useMemo (for React) or computed (for Vue)
// to avoid redundant computations
const diff = differ.diff(before, after);
console.log(diff);
`

You can use your own component to visualize the diff data, or use the built-in viewer:

`tsx
import { Viewer } from 'json-diff-kit';
import type { DiffResult } from 'json-diff-kit';

import 'json-diff-kit/dist/viewer.css';

interface PageProps {
diff: [DiffResult[], DiffResult[]];
}

const Page: React.FC = props => {
return (
diff={props.diff} // required
indent={4} // default 2
lineNumbers={true} // default false
highlightInlineDiff={true} // default false
inlineDiffOptions={{
mode: 'word', // default "char", but "word" may be more useful
wordSeparator: ' ', // default "", but " " is more useful for sentences
}}
/>
);
};
`

The result is here:

!The result (using LCS array diff method).

Other Version of Viewer

Here is an experimental Vue version of the Viewer component.

More Complex Usages

Please check the playground page, where you can adjust nearly all parameters and see the result.

CLI Tool

You can use the CLI tool to generate the diff data from two JSON files. Please install the package terminal-kit before using it.

`bash
pnpm add terminal-kit # or make sure it's already installed in your project

Compare two JSON files, output the diff data to the terminal.




You can navigate it using keyboard like less.

jsondiff run path/to/before.json path/to/after.json

Output the diff data to a file.

Notice there will be no side-by-side view since it's not a TTY.

jsondiff run path/to/before.json path/to/after.json -o path/to/result.diff

Use a custom configuration file and output the diff data to a file.

jsondiff run path/to/before.json path/to/after.json -c path/to/config.json -o path/to/result.diff

Print the help message.

jsondiff --help
jsondiff run --help
`

!A screenshot when using CLI.

Algorithm Details

Please refer to the article JSON Diff Kit: A Combination of Several Simple Algorithms.

Features & Roadmap

- [x] Provide a Differ class and a Viewer component
- [x] Merge "remove & add" at the same place as a modification
- [x] Support inline diffing by word instead of by character
- [x] Generate code directly in the demo page (covered by playground)
- [x] Optimise Viewer performance by adding virtual scrolling
- [x] Add CLI tool
- [x] Provide a Vue version of Viewer`
- [ ] Improve unit tests

License

MIT

[npm-url]: https://npmjs.org/package/json-diff-kit
[npm-image]: https://img.shields.io/npm/v/json-diff-kit.svg

[download-badge]: https://img.shields.io/npm/dm/json-diff-kit.svg