> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/packages/data/diff.md).

# diff

> Text/line/word diffing

Use `diff` to compare text by line, word, or character and render the result as plain text, HTML, JSON, or unified diff text.

```javascript
import "std:diff"
```

## API reference

### `diff`

| Method                                                | Returns      | Description                                                                   |
| ----------------------------------------------------- | ------------ | ----------------------------------------------------------------------------- |
| `diff.compareLines(oldLines: array, newLines: array)` | `DiffResult` | Compares every positional line, including all trailing additions or removals. |
| `diff.compareWords(oldText: string, newText: string)` | `DiffResult` | Uses the shared positional comparison engine on whitespace-delimited words.   |
| `diff.tokenize(text: string)`                         | `array`      | Splits text using standard Unicode whitespace rules.                          |
| `diff.text(oldStr: string, newStr: string)`           | `DiffResult` | Runs the text operation.                                                      |
| `diff.words(oldStr: string, newStr: string)`          | `DiffResult` | Runs the words operation.                                                     |
| `diff.chars(oldStr: string, newStr: string)`          | `DiffResult` | Runs the chars operation.                                                     |
| `diff.unified(result: DiffResult)`                    | `string`     | Runs the unified operation.                                                   |
| `diff.html(result: DiffResult)`                       | `string`     | Renders escaped HTML using a reusable single-pass replacer.                   |
| `diff.json(result: DiffResult)`                       | `string`     | Serializes the tagged result directly without an intermediate object.         |

## Notes

* Prefer `import "std:diff"`; the older `import "osl/diff"` spelling remains supported.
* Return values such as `array` and `object` are regular OSL values unless a returned object section says otherwise.

Line, word, and Unicode character comparisons share one builder-backed engine.