---
title: API reference (Core)
description: The full Core surface - VFS, compile/layout, notifications, render/export, IDE features, fonts/packages, lifecycle, and the methods that are not implemented.
---

# API reference (`Core`)

The full `Core` surface. It flags the methods that look callable but are
**stubs**.

## VFS

| method | notes |
|---|---|
| `create(path, mime, data)` | add a file. `data` is `string` or `Uint8Array`. mime for Typst is `text/x-typst`. |
| `edit(path, edits)` | apply `{ range: { start, end }, replacement }[]` - **UTF-8 byte** offsets. |
| `move(from, to, mime?)` | rename/move a file. |
| `delete(path)` | remove a file. |
| `clear()` | wipe the VFS. |

After the main file is set, any `create`/`edit`/`move`/`delete` to it or a
dependency triggers a recompile automatically.

## Compile & layout

| method | notes |
|---|---|
| `setMain(path, silent?)` | set the document root; triggers the first compile. |
| `setTarget(target)` | `'pdf' \| 'svg' \| 'png' \| 'html' \| 'none'`. Independent of the canvas path - use `'svg'` for a canvas-only preview. |

## Notifications

`on(name, fn)` returns an unsubscribe function. Convenience wrappers:
`onPages`, `onDiagnostics`, `onStatus`, `onOutline`.

| channel | payload | notes |
|---|---|---|
| `pages` | `{ pages: PageInfo[] }` | fires on every layout change. `PageInfo = { width, height }` in points. |
| `diagnostics` | `{ diagnostics: Diagnostic[] }` | errors + warnings; spelling uses a `'misspelling'` severity. |
| `status` | `{ status: 'ok'\|'busy'\|'error'\|'crashed', message? }` | |
| `outline` | `{ entries: OutlineEntry[] }` | heading outline; `position.page` is 0-based. See [Rendering](./Rendering#outline). |

## Render & export

| method | notes |
|---|---|
| `render(index, zoom)` | returns `{ data: Uint8ClampedArray, width }` for one page. |
| `export(args)` | typed `ExportArgs` union -> `{ data, mime }`. See [Rendering](./Rendering#export). |

`ExportArgs`:

```ts
type ExportArgs =
  | { format: 'pdf'; standards?: PdfStandard[] }
  | { format: 'svg'; index: number }
  | { format: 'png'; index: number; ppi?: number }
  | { format: 'html' };
```

`PdfStandard` is a version string (`'1.4'..'2.0'`) or a conformance level
(`'a-1b'`, `'a-2b'`, ..., `'a-4'`, `'ua-1'`). See [Rendering](./Rendering#export).

## IDE features

| method | notes |
|---|---|
| `tags()` | highlight tag table (`typ-strong`, `typ-emph`, ...). Used by the editor bindings. |
| `highlight(path)` | flat `Uint32Array` of `[start, end, tagIndex]` triples. |
| `autocomplete(path, cursor, explicit?)` | `{ from, completions }` or `null`. |
| `tooltip(path, cursor, side?)` | `{ html }` or `null`. |
| `definition(path, cursor, side?)` | source location or `null`. |
| `jumpFromCursor(path, cursor)` | source -> preview positions. |
| `jumpFromClick({ index, x, y })` | preview click -> source/url/position. |
| `syntaxTree(path)` | raw parse tree. |
| `configureSpellCheck(enabled, dict?)` | toggles the feature; the actual check is delegated to JS - see [CodeMirror spellcheck](./CodeMirror#extras). |

## Fonts & packages

`addFont`, `addFonts`, `addFontStubs` ([Fonts](./Fonts)); `setRemotePackages`
([Packages](./Packages)).

## Lifecycle

| method | notes |
|---|---|
| `destroy()` | tear down the worker. |
| `revive()` | rebuild the worker and **replay** all stateful ops (files, fonts, target, main) and re-subscribe. Use after a `'crashed'` status. |

## Not implemented (these throw / no-op - don't build on them)

| method | behavior |
|---|---|
| `eval(expr)` | throws `eval not implemented`. |
| `archive('zip')` | throws `archive not implemented`. |
| `references(...)` | returns `null`. |
| font **index** decoder | JSON only. |