https://github.com/marcelgarus/list_diff

📃 Calculates a minimal list of operations that convert one list into another if applied in order.
https://github.com/marcelgarus/list_diff

Last synced: 8 days ago
JSON representation

📃 Calculates a minimal list of operations that convert one list into another if applied in order.

• Host: GitHub
• URL: https://github.com/marcelgarus/list_diff
• Owner: MarcelGarus
• License: bsd-2-clause
• Created: 2019-10-09T01:08:20.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2022-01-07T17:41:54.000Z (almost 3 years ago)
• Last Synced: 2024-05-01T15:33:37.868Z (6 months ago)
• Language: Dart
• Size: 114 KB
• Stars: 10
• Watchers: 3
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

Awesome Lists containing this project

README

        
Offers a `diff` method that accepts two `List`s and returns a list of

`Operation`s for turning the first list into the second one:

```dart

var operations = await diff(

  ['coconut', 'nut', 'peanut'],

  ['kiwi', 'coconut', 'maracuja', 'nut', 'banana'],

);

operations.forEach(print);

// Operations:

// Insertion of kiwi at 0.

// Insertion of maracuja at 2.

// Insertion of banana at 4.

// Deletion of peanut at 5.

```

`Operation`s are either an insertion or deletion of an item at an index. You

can also directly apply them to a list:

```dart

// Let's try it out!

var fruitBowl = ['coconut', 'nut', 'peanut'];

for (var operation in operations) {

  fruitBowl.apply(operation);

}

// Transforming:

// [coconut, nut, peanut]

// [kiwi, coconut, nut, peanut]

// [kiwi, coconut, maracuja, nut, peanut]

// [kiwi, coconut, maracuja, nut, banana, peanut]

// [kiwi, coconut, maracuja, nut, banana]

```

The lists' items are compared using their `==` operator and `hashCode` by default.

But you can specify a custom comparison method and hash code:

```dart

var operations = await diff(

  first,

  second,

  areEqual: (a, b) => ...,

  getHashCode: (a) => ...,

);

```

### A word about performance and threading

I'm not sure the current version is as performant as it could be.

The runtime is currently O(N*M), where N and M are the lengths of the lists.

If you know a better algorithm, feel welcome to open an issue or file a pull request.

If the data sets are large, the `diff` function automatically spawns an

isolate. If you want more control on whether an isolate should be

spawned, you can also explicitly set the `spawnIsolate` parameter:

```dart

var operations = await diff(first, second, spawnIsolate: true);

```

### For Flutter users

`diff` can be used to calculate updates for an `AnimatedList`.

The [implicitly_animated_list](https://pub.dev/packages/implicitly_animated_list) package does that for you.