object-diff-ast

🌳 Compares two javascript objects and calculates the difference

---

How to use

Install

npm i object-diff-ast

or

yarn add object-diff-ast

Importing

ES6

import { getDiff, render, getConfigDiff } from 'object-diff-ast'

ES5

const objDiff = require('object-diff-ast');

Functions

• getDiff(originalObj, updatedObj) - returns the difference of original and updated objects as list of AST nodes.
• render(nodes, format?) - renders list of AST nodes as formatted string
• getConfigDiff(path1, path2, format?) - returns diff of to files as formatted string (nodejs env). Supported file extensions: .json, .ini or .yaml

Supported formats: "plain", "json" or "complex" (default)

Usage

getDiff

Returns list of diff objects (Node) that represents difference of two objects.

import { getDiff, JSONObject, Node } from 'object-diff-ast';
const before: JSONObject = {
  field1: 'smth',
  field2: 2,
  field3: true,
  deep: {
    field: {
      k: 'v1',
    },
  },
};

const after: JSONObject = {
  field1: 'smth',
  field2: 3,
  field4: {
    foo: 'bar',
  },
  deep: {
    field: {
      k: 'v2',
    },
  },
};

const diff: Node[] = getDiff(before, after);
console.log(diff);
// output >>>
/*
[
  { key: 'field1', level: 1, type: 'unchanged', oldValue: 'smth' },
  { key: 'field2', level: 1, type: 'changed', oldValue: 2, newValue: 3 },
  { key: 'field3', level: 1, type: 'removed', oldValue: true },
  {
    key: 'deep',
    level: 1,
    type: 'unit',
    unit: 'object',
    children: [
      {
        key: 'field',
        level: 2,
        type: 'unit',
        unit: 'object',
        children: [
          {
            key: 'k',
            level: 3,
            type: 'changed',
            oldValue: 'v1',
            newValue: 'v2',
          },
        ],
      },
    ],
  },
  { key: 'field4', level: 1, type: 'added', newValue: { foo: 'bar' } },
]
*/

Or with arrays as field values

import { getDiff, JSONObject, Node } from 'object-diff-ast';

const before: JSONObject = {
  field: ['first', 'second'],
};

const after: JSONObject = {
  field: ['first', 'third'],
  newField: [1, 2, 3],
};
const diff: Node[] = getDiff(before, after);
console.log(diff);
// output >>>
/*
[
  {
    key: 'field',
    level: 1,
    type: 'unit',
    unit: 'array',
    children: [
      { key: '0', level: 2, type: 'unchanged', oldValue: 'first' },
      { key: '1', level: 2, type: 'changed', oldValue: 'second', newValue: 'third' },
    ],
  },
  { key: 'newField', level: 1, type: 'added', newValue: [1, 2, 3] },
];
*/

render

Renders calculated diff in different formats.

import { getDiff, render, JSONObject } from 'object-diff-ast';

const before: JSONObject = {
  field1: 'smth',
  field2: 2,
  field3: true,
  deep: {
    foo: {
      bar: 'v1',
    },
    list: [1, 2],
  },
};

const after: JSONObject = {
  field1: 'smth',
  field2: 3,
  field4: {
    foo: 'bar',
  },
  deep: {
    foo: {
      bar: 'v2',
    },
    list: [1, 3, 4],
  },
};

const diff = getDiff(before, after);

const complex: string = render(diff); // default format = "complex"
console.log(complex);
// String output >>>
/*
{
    field1: smth
  + field2: 3
  - field2: 2
  - field3: true
    deep: {
        foo: {
          + bar: v2
          - bar: v1
        }
        list: [
            0: 1
          + 1: 3
          - 1: 2
          + 2: 4
        ]
    }
  + field4: {
        foo: bar
    }
}
*/

const plain = render(diff, 'plain');
console.log(plain);
// String output >>>
/*
Property 'field2' was updated. From '2' to '3'
Property 'field3' was removed
Property 'deep.foo.bar' was updated. From 'v1' to 'v2'
Property 'deep.list.1' was updated. From '2' to '3'
Property 'deep.list.2' was added with value '4'
Property 'field4' was added with complex value
*/

const json = render(diff, 'json'); // just the stringified diff object
console.log(json);
// String output >>>
/*
[
  {
    "key": "field1",
    "level": 1,
    "type": "unchanged",
    "oldValue": "smth"
  },
  {
    "key": "field2",
    "level": 1,
    "type": "changed",
    "oldValue": 2,
    "newValue": 3
  },
  {
    "key": "field3",
    "level": 1,
    "type": "removed",
    "oldValue": true
  },
  {
    "key": "deep",
    "level": 1,
    "type": "unit",
    "unit": "object",
    "children": [
      {
        "key": "foo",
        "level": 2,
        "type": "unit",
        "unit": "object",
        "children": [
          {
            "key": "bar",
            "level": 3,
            "type": "changed",
            "oldValue": "v1",
            "newValue": "v2"
          }
        ]
      },
      {
        "key": "list",
        "level": 2,
        "type": "unit",
        "unit": "array",
        "children": [
          {
            "key": "0",
            "level": 3,
            "type": "unchanged",
            "oldValue": 1
          },
          {
            "key": "1",
            "level": 3,
            "type": "changed",
            "oldValue": 2,
            "newValue": 3
          },
          {
            "key": "2",
            "level": 3,
            "type": "added",
            "newValue": 4
          }
        ]
      }
    ]
  },
  {
    "key": "field4",
    "level": 1,
    "type": "added",
    "newValue": {
      "foo": "bar"
    }
  }
]
*/

getConfigDiff

Wrapper over the render function. Returns diff of two configuration files as formatted string. (only Nodejs environment) Support json, ini and yaml file extensions.

import { getConfigDiff } from 'object-diff-ast';

const complexMessage = getConfigDiff('/Users/me/config1.yaml', '/Users/me/config2.yaml');

const plainMessage = getConfigDiff('/Users/me/config1.json', '/Users/me/config2.json', 'plain');

const jsonMessage = getConfigDiff('/Users/me/config1.ini', '/Users/me/config2.ini', 'json');

---

Console app

You also can use this package as nodejs console app.

App installation

npm i -g object-diff-ast

Usage

getdiff ./config1.yaml ./config2.yaml

or

getdiff ./config1.yaml ./config2.yaml -f plain