[mkroemer]

Builds on #7 (components), #6 (UI texts), #5 (icons) and #4 (theming). It also carries three commits that move the document, sheet and slide views onto the strings table from #6 (feat(docx|xlsx|pptx): … read their texts from the strings table), because the controller's outline and status use those texts. I can open those three as PRs of their own if you would rather review them apart. The headless part is the last commit.

This lets a host draw its own controls around the document: zoom, page, outline, Edit/Save, undo, in its own toolbar and side panel.

const ctl = createViewerController()

<MyToolbar controller={ctl} />
<DocViewer src={file} controller={ctl} headless />

function MyToolbar({ controller }) {
  const s = useViewerState(controller)
  return <>
    <button disabled={!s.canUndo} onClick={() => controller.undo()}>Undo</button>
    <button onClick={() => controller.zoomIn()}>{s.zoom && Math.round(s.zoom.effective * 100)} %</button>
  </>
}

headless leaves the viewer with the document alone: no top bar, zoom control, outline panel or button, sheet tabs, slide list or Present button. While editing, the formatting toolbar keeps its row, and an explicit toolbar brings back the top bar (File menu, comments, Save).

The controller (src/react/controller.ts, no React inside) holds the state: kind, loading, editing, canEdit, dirty, saving, canUndo/canRedo, zoom, page, outline (headings, sheets or slides) and status. It runs the commands: setEditing, save, undo, redo, zoomIn/zoomOut/setZoom, goto, gotoPage, present, print, fileAction, toggleComments. The viewer and its view publish to it and register their commands. Without a controller from the host the viewer keeps its own, so nothing changes for existing users. When the viewer unmounts its part of the state is cleared, so a controller that outlives it shows no document.

Per kind:

• DOCX: the headings are read for the controller whether or not the outline panel is open, with the current one. The heading jumped to stays current while its page is in view. Undo and redo are offered only while editing.
• XLSX: the visible sheets are the outline. Undo and redo are counted per edit and cleared when a sheet is added, deleted, moved, renamed or imported, as the worker's history is. Switching sheets through the controller keeps a formula being typed open, for cross-sheet references, as the built-in tabs do.
• PPTX: slides are titled by their title placeholder, read by a new title-only worker call (pptx.titles, no layout), and only while a host subscribes (observed, watchObserved), so the plain viewer does no extra work. Titles follow edits. Symbol-font characters in titles become their Unicode look-alikes.

Also: onLoad fires once per opened document, also with an inline callback; mount() returns the controller and <office-viewer headless> has .controller; the e2e harness takes PLAYWRIGHT_CHANNEL to use an installed browser.

Two follow-ups would build on this one: formatting state and commands through the controller (ViewerState.format, ctl.format(...), for a host's own formatting toolbar), and ready-made controls (ZoomBar, StatusText, OutlineList, SheetTabs, FormatBar) for hosts that want the engine's controls in their own layout.

test/controller.test.ts covers the state, commands, zoom steps and clearing; e2e/controller.spec.ts drives DOCX, XLSX and PPTX through the controller with no chrome mounted, including editing, saving and undo only while editing. bun run typecheck and bun test pass; the e2e suite runs in CI.

🤖 Generated with Claude Code