mercyscope / json-difference

A simple way to find the difference between two objects or json diff

JsonDifference

Computes the difference between two objects and returns an intuitive result. No matter how big your JSON is, the diff will be returned pretty fast.

The question you should ask is: Given my old structure what was changed, removed or added to the new structure?

This repository contains two npm packages, json-difference and its cli version (json-difference-cli).

It's a very lightweight lib that costs only 🪶 1.95 kB │ gzip: 0.79 kB.

Live Demo

Master (deprecated link) Latest release (new)

Installation

yarn add json-difference


# If you want to play with the terminal version
yarn add json-difference-cli

Or

<script type="module">
  // https://json-difference.s3.amazonaws.com/<a.b.c>/json-difference-<a.b.c>.mjs
  import { getDiff } from 'https://json-difference.s3.amazonaws.com/1.16.0/json-difference-1.16.0.mjs'
</script>

Example

Running example:

yarn example {simple, stress}

Usage of Json Difference

Method:

getDiff(oldStruct, newStruct)

Returns the structural difference between oldStruct and newStruct.

Simple usage:

import { getDiff } from 'json-difference'

const coffee = { color: { color1: 'black', color2: 'brown' }, special: true }
const oil = { color: { color1: 'red', color2: 'blue' }, special2: false, especial3: [{}] }

// Get JsonDiff delta
const diff = getDiff(coffee, oil)
const diff2 = getDiff(coffee, oil, { isLodashLike: true })

console.log(diff)
console.log(diff2)

Output:

{
  "added": [
    ["special2", false],
    ["especial3", []],
    ["especial3/0[]", {}]
  ],
  "removed": [["special", true]],
  "edited": [
    ["color/color1", "black", "red"],
    ["color/color2", "brown", "blue"]
  ]
}

{
  "added": [
    ["special2", false],
    ["especial3", []],
    ["especial3[0]", {}]
  ],
  "removed": [["special", true]],
  "edited": [
    ["color.color1", "black", "red"],
    ["color.color2", "brown", "blue"]
  ]
}

Usage of Json Difference CLI

# jd -> Json Difference command
# -o -> Original or old struct
# -m -> Modified or new struct
jd -o "{}" -m "[]"

Delta

The delta is an object that contains three properties that follow a pattern. This pattern will be shown below:

Operation	Pattern
"edited"	[path_to_the_key, old_value, new_value]
"added"	[path_to_the_key, value]
"removed"	[path_to_the_key, old_value]

value	Explanation
"root"	Indicates the root of the object
"@{}"	Indicates that the key is a non-leaf node of type Object
"@[]"	Indicates that the key is a non-leaf node of type Array

Some operations

JSON original	JSON modified	Delta
{}	[]	"edited": [ [ "root", {}, [] ] ]
[]	{}	"edited": [ [ "root", [], {} ] ]
[{}]	[[]]	"edited": [ [ "0[]", {}, [] ] ]
{"a": "b"}	{"a": "c"}	"edited": [ [ "a", "b", "c" ] ]
{"":""}	{"": "a"}	"edited": [ [ "", "", "a" ] ]
{"":{"":""}}	{"": {"": "a"}}	"edited": [ [ "/", "", "a" ] ]
[]	[{}]	"added": [ [ "0[]", {} ] ]
{}	{"a":"b"}	"added": [ [ "a", "b" ] ]
{"a":"b"}	{}	"removed": [ [ "a", "b" ] ]
[{}]	[]	"removed": [ [ "0[]", {} ] ]
[{"":""}]	{"":""}	"added": [ [ "", "" ] ], "removed": [ [ "0[]", {} ], [ "0[]/", "" ] ], "edited": [ [ "root", [], {} ] ]

It is important to understand that the output generated by the latest versions of Json Difference: v1.9.1 and V1.15.7 is different. Version V1.15.7 introduces greater accuracy for the return.

Anyway, to request a new feature or report a problem, just open an issue and it will be investigated.