https://github.com/newxps/var-diff

javascript variable diff algorithm
https://github.com/newxps/var-diff

Last synced: 16 days ago
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javascript variable diff algorithm

• Host: GitHub
• URL: https://github.com/newxps/var-diff
• Owner: newxps
• License: mit
• Created: 2019-05-13T10:51:21.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2022-12-30T17:43:14.000Z (almost 2 years ago)
• Last Synced: 2024-09-23T02:09:51.929Z (about 2 months ago)
• Language: JavaScript
• Homepage:
• Size: 146 KB
• Stars: 6
• Watchers: 1
• Forks: 0
• Open Issues: 9
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        


# var-diff

get the difference between two variables



  

    

  

  

    

  



### Compatibility

|   IE     | Chrome | Firefox  | Opera |  Safari     |

|   :-:    |  :-:   |   :-:    | :-:   |   :--:      |

|    ✔️    |   ✔️   |   ✔️     |  ✔️  |    ✔️       |

### Installation

```bash

npm i var-diff

```

or

```html

```

### Usage

use `var patches = diff.get(origin, target, [key])` to get difference `patches` between origin and target variables.

`key` is an optional parameter used to improve sorting performance.

`patches` is an array containing all of the differences betwen two variables

```

// patches

t: type   1-create 2-delete 3-edit 4-replace

p: path {Array}

v: value

i: new index(when type is replace)

```

use `diff.apply(origin, patches)` to make the origin variable apply the `patches` then become the target varible. but all references of the origin variable are reserved.

```javascript

const diff = require('var-diff');

let a = [1, 2, 3, {id: 1, name: 'tom'}, {id: 2, name: 'jack'}]

let b = [2, {id: 2, name: 'will'}, 3, {id: 1, name: 'lucy'}]

let patches = diff.get(origin, target, 'id');

console.log(patches);

/**

 * patches

[ 

  { t: 2, p: [ 0 ] },                       // remove the 0th element 

  { t: 3, p: [ 2, 'name' ], v: 'lucy' },    // update the name of the 2th element to 'lucy'

  { t: 3, p: [ 3, 'name' ], v: 'will' },    // update the name of the 3th element to 'will'

  { t: 4, p: [ 3 ], i: 1 },                 // change the 3th element to the 1th position

  { t: 4, p: [ 3 ], i: 2 }                  // change the 3th element to the 2th position

]

 */

a = diff.apply(a, patches);

console.log(JSON.stringify(a) === JSON.stringify(b));

// true

```

### Examples

```javascript

var a = {

  name: 'tom',

  gender: 'male',

  list: [{

    id: 1,

    label: 'teacher'

  }]

}

var b = {

  name: 'jack',

  list: [{

    id: 2,

    label: 'worker'

  }, {

    id: 3,

    label: 'student'

  }, {

    id: 1,

    label: ''

  }]

}

p = diff.get(a, b, 'id');

console.log(p);

/**

  t: type   1-create 2-delete 3-edit 4-replace

  p: path {Array}

  v: value

  i: new index(when type is replace)

 [{ t: 3, p: [ 'name' ], v: 'jack' },

  { t: 2, p: [ 'gender' ] },

  { t: 3, p: [ 'list', 0, 'label' ], v: '' },

  { t: 1, p: [ 'list', 1 ], v: { id: 2, label: 'worker' } },

  { t: 1, p: [ 'list', 2 ], v: { id: 3, label: 'student' } },

  { t: 4, p: [ 'list', 0 ], i: 2 },

  { t: 4, p: [ 'list', 1 ], i: 0 },

  { t: 1, p: [ 'age' ], v: 25 }]

 */

var aa = diff.apply(a, p, 'id'); // key

console.log(JSON.stringify(aa) === JSON.stringify(b));  // true

```

```javascript

var a = [NaN, NaN];

var b = [NaN, NaN];

var p = diff.get(a, b, 'id');

console.log(p); // []

```

### LICENSE

MIT