json-diff-ts

A diff tool for JavaScript based on https://www.npmjs.com/package/diff-json (viruschidai@gmail.com) rewritten in TypeScript.

The most compelling feature of this diff library is the support for array keys instead of just indexes and is compatible with JSONPath.

Features

diff

If a key is specified for an embedded array, the diff will be generated based on the objects have same keys.

Examples:

1
2  var changesets = require('diff-json-ts');
3  var newObj, oldObj;
4
5  oldObj = {
6    name: 'joe',
7    age: 55,
8    coins: [2, 5],
9    children: [
10      {name: 'kid1', age: 1},
11      {name: 'kid2', age: 2}
12    ]};
13
14  newObj = {
15    name: 'smith',
16    coins: [2, 5, 1],
17    children: [
18      {name: 'kid3', age: 3},
19      {name: 'kid1', age: 0},
20      {name: 'kid2', age: 2}
21    ]};
22
23
24  // Assume children is an array of child object and the child object has 'name' as its primary key
25  diffs = changesets.diff(oldObj, newObj, {children: 'name'}); // keys can also be hierarchical e.g. {children: 'name', 'children.grandChildren', 'age'}
26
27  expect(diffs).to.eql([
28    {
29      type: 'update', key: 'name', value: 'smith', oldValue: 'joe'
30    },
31    {
32      type: 'update', key: 'coins', embededKey: '$index', changes: [
33          {type: 'add', key: '2', value: 1 }
34        ]
35    },
36    {
37      type: 'update',
38      key: 'children',
39      embededKey: 'name',
40      changes: [
41        {
42          type: 'update', key: 'kid1', changes: [
43            {type: 'update', key: 'age', value: 0, oldValue: 1 }
44          ]
45        },
46        {
47          type: 'add', key: 'kid3', value: {name: 'kid3', age: 3 }
48        }
49      ]
50    },
51    {
52      type: 'remove', key: 'age', value: 55
53    }
54  ]);

flattenChangeset

Converts the changeset into a flat atomic change list compatible with JSONPath.

Examples:

1const flatChanges = flattenChangeset(diffs);
2// convert changes back to changeset format
3const changeset = unflattenChanges(flatChanges.slice(1, 5));
4// or use a JSONPath library to apply the patches
5// ...

The flatChange format will look like this:

1[
2  { type: 'UPDATE', key: 'name', value: 'smith', oldValue: 'joe', path: '$.name', valueType: 'String' },
3  { type: 'REMOVE', key: 'mixed', value: 10, path: '$.mixed', valueType: 'Number' },
4  { type: 'UPDATE', key: 'inner', value: 2, oldValue: 1, path: '$.nested.inner', valueType: 'Number' },
5  {
6    type: 'UPDATE',
7    key: 'date',
8    value: '2014-10-12T09:13:00.000Z',
9    oldValue: '2014-10-13T09:13:00.000Z',
10    path: '$.date',
11    valueType: 'Date'
12  },
13  { type: 'ADD', key: '2', value: 1, path: '$.coins[2]', valueType: 'Number' },
14  { type: 'REMOVE', key: '0', value: 'car', path: '$.toys[0]', valueType: 'String' },
15  { type: 'REMOVE', key: '1', value: 'doll', path: '$.toys[1]', valueType: 'String' },
16  { type: 'REMOVE', key: '0', path: '$.pets[0]', valueType: 'undefined' },
17  { type: 'REMOVE', key: '1', value: null, path: '$.pets[1]', valueType: null },
18  { type: 'UPDATE', key: 'age', value: 0, oldValue: 1, path: "$.children[?(@.name='kid1')].age", valueType: 'Number' },
19  {
20    type: 'UPDATE',
21    key: 'value',
22    value: 'heihei',
23    oldValue: 'haha',
24    path: "$.children[?(@.name='kid1')].subset[?(@.id='1')].value",
25    valueType: 'String'
26  },
27  {
28    type: 'REMOVE',
29    key: '2',
30    value: { id: 2, value: 'hehe' },
31    path: "$.children[?(@.name='kid1')].subset[?(@.id='2')]",
32    valueType: 'Object'
33  },
34  { type: 'ADD', key: 'kid3', value: { name: 'kid3', age: 3 }, path: '$.children', valueType: 'Object' }
35];

applyChange

Examples:

1
2  var changesets = require('diff-json-ts');
3  var oldObj = {
4    name: 'joe',
5    age: 55,
6    coins: [2, 5],
7    children: [
8      {name: 'kid1', age: 1},
9      {name: 'kid2', age: 2}
10    ]};
11
12
13  // Assume children is an array of child object and the child object has 'name' as its primary key
14  diffs = [
15    {
16      type: 'update', key: 'name', value: 'smith', oldValue: 'joe'
17    },
18    {
19      type: 'update', key: 'coins', embededKey: '$index', changes: [
20          {type: 'add', key: '2', value: 1 }
21        ]
22    },
23    {
24      type: 'update',
25      key: 'children',
26      embededKey: 'name', // The key property name of the elements in an array
27      changes: [
28        {
29          type: 'update', key: 'kid1', changes: [
30            {type: 'update', key: 'age', value: 0, oldValue: 1 }
31          ]
32        },
33        {
34          type: 'add', key: 'kid3', value: {name: 'kid3', age: 3 }
35        }
36      ]
37    },
38    {
39      type: 'remove', key: 'age', value: 55
40    }
41  ]
42
43  changesets.applyChanges(oldObj, diffs)
44  expect(oldObj).to.eql({
45    name: 'smith',
46    coins: [2, 5, 1],
47    children: [
48      {name: 'kid3', age: 3},
49      {name: 'kid1', age: 0},
50      {name: 'kid2', age: 2}
51    ]});
52

revertChange

Examples:

1
2  var changesets = require('diff-json-ts');
3
4  var newObj = {
5    name: 'smith',
6    coins: [2, 5, 1],
7    children: [
8      {name: 'kid3', age: 3},
9      {name: 'kid1', age: 0},
10      {name: 'kid2', age: 2}
11   ]};
12
13  // Assume children is an array of child object and the child object has 'name' as its primary key
14  diffs =  [
15    {
16      type: 'update', key: 'name', value: 'smith', oldValue: 'joe'
17    },
18    {
19      type: 'update', key: 'coins', embededKey: '$index', changes: [
20          {type: 'add', key: '2', value: 1 }
21        ]
22    },
23    {
24      type: 'update',
25      key: 'children',
26      embededKey: 'name', // The key property name of the elements in an array
27      changes: [
28        {
29          type: 'update', key: 'kid1', changes: [
30            {type: 'update', key: 'age', value: 0, oldValue: 1 }
31          ]
32        },
33        {
34          type: 'add', key: 'kid3', value: {name: 'kid3', age: 3 }
35        }
36      ]
37    },
38    {
39      type: 'remove', key: 'age', value: 55
40    }
41  ]
42
43  changesets.revertChanges(newObj, diffs)
44  expect(newObj).to.eql {
45    name: 'joe',
46    age: 55,
47    coins: [2, 5],
48    children: [
49      {name: 'kid1', age: 1},
50      {name: 'kid2', age: 2}
51    ]};
52

Get started

npm install diff-json-ts

Run the test

npm run test

Contact

Blog: https://blog.leitwolf.io

Twitter: @cglessner

Licence

The MIT License (MIT)

Copyright (c) 2019 Christian Glessner

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

The project is based on diff-json (https://www.npmjs.com/package/diff-json). Copyright 2013 viruschidai@gmail.com. for additional details.

Original License

The MIT License (MIT)

Copyright (c) 2013 viruschidai@gmail.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.