https://github.com/christianhg/diff-trees
For diffing ordered trees
https://github.com/christianhg/diff-trees
diff-trees
Last synced: 7 months ago
JSON representation
For diffing ordered trees
- Host: GitHub
- URL: https://github.com/christianhg/diff-trees
- Owner: christianhg
- License: mit
- Created: 2020-11-25T18:55:14.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2022-11-09T21:21:24.000Z (over 3 years ago)
- Last Synced: 2024-04-24T22:01:03.102Z (almost 2 years ago)
- Topics: diff-trees
- Language: TypeScript
- Homepage:
- Size: 1.07 MB
- Stars: 4
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# diff-trees
> For diffing ordered trees
[](https://www.npmjs.org/package/diff-trees)
A single `diffTrees` function is exported:
```ts
declare function diffTrees(
treeA: TreeNode<{ value: TValue }>,
treeB: TreeNode<{ value: TValue }>
): DiffTree;
```
It takes two trees of type `TreeNode`:
```ts
type TreeNode = {
id: string;
children: TreeNode[];
} & TValues;
```
And produces a single tree of type `DiffTree` which is an array containing one or two `DiffTreeNode`s. The second `DiffTreeNode` is included if the root of the tree was deleted.
```ts
type DiffTree =
| [DiffTreeNode]
| [DiffTreeNode, DiffTreeNode];
```
```ts
type DiffTreeNode = Omit, 'children'> & {
change: Change;
children: DiffTreeNode[];
};
```
Where a `Change` is:
```ts
type Change =
| [ChangeType.Unchanged]
| [ChangeType.Inserted]
| [ChangeType.Deleted]
| [ChangeType.Updated]
| [ChangeType.Moved]
| [ChangeType.Moved, ChangeType.Updated];
```
- `ChangeType.Unchanged` denotes unchanged nodes.
- `ChangeType.Inserted` denotes new nodes.
- `ChangeType.Deleted` denotes deleted nodes.
- `ChangeType.Updated` denotes nodes where the `value` changed.
- `ChangeType.Moved` denotes nodes that moved to another subtree or changed place within the same subtree.
---
The `value` in a `TreeNode` can is generic. If the `value` has changed, the `DiffTreeNode` is annotated with `ChangeType.Updated`. By default, values are compared using [strict equality (`===`)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality). To change how values are compared, add a custom `valueEquality` function to the optional `options` object:
```ts
declare function diffTrees(
treeA: TreeNode<{ value: TValue }>,
treeB: TreeNode<{ value: TValue }>,
options?: {
valueEquality: (a: TValue, b: TValue) => boolean;
}
): DiffTreeNode;
```
## Examples
```ts
diffTrees(
{ id: '1', value: 'a', children: [] },
{ id: '1', value: 'a', children: [] }
);
// =>
[
{
id: '1',
value: 'a',
children: [],
change: [ChangeType.Unchanged],
},
];
```
```ts
diffTrees(
{ id: '1', value: 'a', children: [] },
{ id: '2', value: 'b', children: [] }
);
// =>
[
{
id: '2',
value: 'b',
children: [],
change: [ChangeType.Inserted],
},
{
id: '1',
value: '1',
children: [],
change: [ChangeType.Deleted],
},
];
```
```ts
diffTrees(
{ id: '1', value: 'a', children: [] },
{ id: '1', value: 'a', children: [{ id: '2', value: 'b', children: [] }] }
);
// =>
[
{
id: '1',
value: 'a',
change: [ChangeType.Unchanged],
children: [
{ id: '2', value: 'b', change: [ChangeType.Inserted], children: [] },
],
},
];
```
```ts
diffTrees(
{
id: '1',
value: 'a',
children: [
{ id: '2', value: 'b', children: [] },
{ id: '3', value: 'c', children: [] },
],
},
{
id: '1',
value: 'a',
children: [
{ id: '3', value: 'c2', children: [] },
{ id: '2', value: 'b', children: [] },
],
}
);
// =>
[
{
id: '1',
value: 'a',
change: [ChangeType.Unchanged],
children: [
{
id: '3',
value: 'c2',
change: [ChangeType.Moved, ChangeType.Updated],
children: [],
},
{
id: '2',
value: 'b',
change: [ChangeType.Moved],
children: [],
},
],
},
];
```