Diff & patch JavaScript objects
/dist folder with bundles for UMD, commonjs, or ES modules)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)
And you can test your current browser visiting the test page.
v4.8+// sample data var country = { name: "Argentina", capital: "Buenos Aires", independence: new Date(1816, 6, 9), unasur: true }; // clone country, using dateReviver for Date objects var country2 = JSON.parse(JSON.stringify(country), jsondiffpatch.dateReviver); // make some changes country2.name = "Republica Argentina"; country2.population = 41324992; delete country2.capital; var 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 var reverseDelta = jsondiffpatch.reverse(delta); // also country2 can be return to original value with: jsondiffpatch.unpatch(country2, delta); var delta2 = jsondiffpatch.diff(country, country2); assert(delta2 === undefined) // undefined => no difference
Array diffing:
// sample data var 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 var 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 var rosario = country.cities.splice(1, 1)[0]; rosario.population += 1234; country.cities.push(rosario); // create a configured instance, match objects by name var diffpatcher = jsondiffpatch.create({ objectHash: function(obj) { return obj.name; } }); var 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 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
var jsondiffpatch = require('jsondiffpatch').create(options);
In a browser, you could load directly a bundle in /dist, eg. /dist/jsondiffpatch.umd.js.
var jsondiffpatch = require('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: { // 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> <script type='text/javascript' src="https://cdn.jsdelivr.net/npm/jsondiffpatch/dist/jsondiffpatch.umd.min.js"></script> <link rel="stylesheet" href="./style.css" type="text/css" /> <link rel="stylesheet" href="../formatters-styles/html.css" type="text/css" /> <link rel="stylesheet" href="../formatters-styles/annotated.css" type="text/css" /> </head> <body> <div id="visual"></div> <hr/> <div id="annotated"></div> <script> var left = { a: 3, b: 4 }; var right = { a: 5, c: 9 }; var delta = jsondiffpatch.diff(left, right); // beautiful html diff document.getElementById('visual').innerHTML = jsondiffpatch.formatters.html.format(delta, left); // self-explained json document.getElementById('annotated').innerHTML = jsondiffpatch.formatters.annotated.format(delta, left); </script> </body> </html>
To see formatters in action check the Live Demo.
For more details check Formatters documentation
# diff two json files, colored output (using chalk lib) ./node_modules/.bin/jsondiffpatch ./left.json ./right.json # or install globally npm install -g jsondiffpatch jsondiffpatch ./demo/left.json ./demo/right.json
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.