jsondiffpatch
Advanced tools
jsondiffpatch.com
Diff & patch JavaScript objects
objectHash function (this is how objects are matched, otherwise a dumb match by position is used). For more details, check Array diff documentation./node_modules/.bin/jsondiffpatch left.json right.jsonjsondiffpatch.clone(obj) (deep clone)as a CLI:
npx jsondiffpatch https://jsondiffpatch.com/demo/left.json https://jsondiffpatch.com/demo/right.json
or as a library:
// sample data
const country = {
name: 'Argentina',
capital: 'Buenos Aires',
independence: new Date(1816, 6, 9),
unasur: true,
};
// clone country, using dateReviver for Date objects
const country2 = JSON.parse(JSON.stringify(country), jsondiffpatch.dateReviver);
// make some changes
country2.name = 'Republica Argentina';
country2.population = 41324992;
delete country2.capital;
const delta = jsondiffpatch.diff(country, country2);
assertSame(delta, {
name: ['Argentina', 'Republica Argentina'], // old value, new value
population: ['41324992'], // new value
capital: ['Buenos Aires', 0, 0], // deleted
});
// patch original
jsondiffpatch.patch(country, delta);
// reverse diff
const reverseDelta = jsondiffpatch.reverse(delta);
// also country2 can be return to original value with: jsondiffpatch.unpatch(country2, delta);
const delta2 = jsondiffpatch.diff(country, country2);
assert(delta2 === undefined);
// undefined => no difference
Array diffing:
// sample data
const country = {
name: 'Argentina',
cities: [
{
name: 'Buenos Aires',
population: 13028000,
},
{
name: 'Cordoba',
population: 1430023,
},
{
name: 'Rosario',
population: 1136286,
},
{
name: 'Mendoza',
population: 901126,
},
{
name: 'San Miguel de Tucuman',
population: 800000,
},
],
};
// clone country
const country2 = JSON.parse(JSON.stringify(country));
// delete Cordoba
country.cities.splice(1, 1);
// add La Plata
country.cities.splice(4, 0, {
name: 'La Plata',
});
// modify Rosario, and move it
const rosario = country.cities.splice(1, 1)[0];
rosario.population += 1234;
country.cities.push(rosario);
// create a configured instance, match objects by name
const diffpatcher = jsondiffpatch.create({
objectHash: function (obj) {
return obj.name;
},
});
const delta = diffpatcher.diff(country, country2);
assertSame(delta, {
cities: {
_t: 'a', // indicates this node is an array (not an object)
1: [
// inserted at index 1
{
name: 'Cordoba',
population: 1430023,
},
],
2: {
// population modified at index 2 (Rosario)
population: [1137520, 1136286],
},
_3: [
// removed from index 3
{
name: 'La Plata',
},
0,
0,
],
_4: [
// move from index 4 to index 2
'',
2,
3,
],
},
});
For more example cases (nested objects or arrays, long text diffs) check packages/jsondiffpatch/test/examples/
If you want to understand deltas, see delta format documentation
This works for node, or in browsers if you already do bundling on your app
npm install jsondiffpatch
import * as jsondiffpatch from 'jsondiffpatch';
const jsondiffpatchInstance = jsondiffpatch.create(options);
In a browser, you can load a bundle using a tool like esm.sh or Skypack.
import * as jsondiffpatch from 'jsondiffpatch';
// Only import if you want text diffs using diff-match-patch
import DiffMatchPatch from 'diff-match-patch';
const jsondiffpatchInstance = jsondiffpatch.create({
// used to match objects when diffing arrays, by default only === operator is used
objectHash: function (obj) {
// this function is used only to when objects are not equal by ref
return obj._id || obj.id;
},
arrays: {
// default true, detect items moved inside the array (otherwise they will be registered as remove+add)
detectMove: true,
// default false, the value of items moved is not included in deltas
includeValueOnMove: false,
},
textDiff: {
// If using text diffs, it's required to pass in the diff-match-patch library in through this proprty.
// Alternatively, you can import jsondiffpatch using `jsondiffpatch/with-text-diffs` to avoid having to pass in diff-match-patch through the options.
diffMatchPatch: DiffMatchPatch,
// default 60, minimum string length (left and right sides) to use text diff algorythm: google-diff-match-patch
minLength: 60,
},
propertyFilter: function (name, context) {
/*
this optional function can be specified to ignore object properties (eg. volatile data)
name: property name, present in either context.left or context.right objects
context: the diff context (has context.left and context.right objects)
*/
return name.slice(0, 1) !== '$';
},
cloneDiffValues: false /* default false. if true, values in the obtained delta will be cloned
(using jsondiffpatch.clone by default), to ensure delta keeps no references to left or right objects. this becomes useful if you're diffing and patching the same objects multiple times without serializing deltas.
instead of true, a function can be specified here to provide a custom clone(value)
*/,
});
<!doctype html>
<html>
<head>
<link rel="stylesheet" href="./style.css" type="text/css" />
<link
rel="stylesheet"
href="https://esm.sh/jsondiffpatch@0.6.0/lib/formatters/styles/html.css"
type="text/css"
/>
<link
rel="stylesheet"
href="https://esm.sh/jsondiffpatch@0.6.0/lib/formatters/styles/annotated.css"
type="text/css"
/>
</head>
<body>
<div id="visual"></div>
<hr />
<div id="annotated"></div>
<script type="module">
import * as jsondiffpatch from 'https://esm.sh/jsondiffpatch@0.6.0';
import * as annotatedFormatter from 'https://esm.sh/jsondiffpatch@0.6.0/formatters/annotated';
import * as htmlFormatter from 'https://esm.sh/jsondiffpatch@0.6.0/formatters/html';
const left = { a: 3, b: 4 };
const right = { a: 5, c: 9 };
const delta = jsondiffpatch.diff(left, right);
// beautiful html diff
document.getElementById('visual').innerHTML = htmlFormatter.format(
delta,
left,
);
// self-explained json
document.getElementById('annotated').innerHTML =
annotatedFormatter.format(delta, left);
</script>
</body>
</html>
To see formatters in action check the Live Demo.
For more details check Formatters documentation
diff(), patch() and reverse() functions are implemented using Pipes & Filters pattern, making it extremely customizable by adding or replacing filters on a pipe.
Check Plugins documentation for details.
The deep-diff package provides similar functionality for computing differences between JavaScript objects. It offers a more granular approach to detecting changes, including additions, deletions, and modifications. However, it does not provide built-in patching and unpatching capabilities like jsondiffpatch.
The diff package is a general-purpose text and data comparison tool that can be used to compute differences between strings, arrays, and objects. While it is versatile and widely used, it lacks the specialized JSON diffing and patching features provided by jsondiffpatch.
The fast-json-patch package focuses on applying JSON Patch operations as defined by RFC 6902. It is optimized for performance and provides a simple API for applying and validating JSON patches. However, it does not compute differences between JSON objects, which is a key feature of jsondiffpatch.
FAQs
JSON diff & patch (object and array diff, text diff, multiple output formats)
The npm package jsondiffpatch receives a total of 0 weekly downloads. As such, jsondiffpatch popularity was classified as not popular.
We found that jsondiffpatch demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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