fix: correct slide detection for PowerPoint Online

[EinfachMxrc]

Problem

In PowerPoint Online (SharePoint/OneDrive) blieb die angezeigte Folie dauerhaft auf 1.

Ursache: PowerPoint.run() + getSelectedSlides() gibt in PowerPoint Online immer Folie 1 zurück, unabhängig davon welche Folie gerade angezeigt wird. Diese Methode war bisher als primäre Strategie eingestellt.

Fix

• getSelectedDataAsync(CoercionType.SlideRange) ist jetzt die primäre Methode für alle Plattformen — funktioniert in Online zuverlässig und in Desktop wenn Fokus auf der Präsentation liegt
• PowerPoint.run() + getSelectedSlides() nur noch als Desktop-Fallback (wird in Online via Office.PlatformType.OfficeOnline Check übersprungen)
• Kein Debounce beim DocumentSelectionChanged Handler — liest sofort, solange die Folie noch aktiv ist

Nach dem Merge

Taskpane in PowerPoint Online schließen und neu öffnen — kein Manifest-Re-Download nötig.

🤖 Generated with Claude Code

Summary by CodeRabbit

Release Notes

Bug Fixes

• Improved detection of PowerPoint Online vs Desktop environments for more consistent behavior
• Enhanced slide information retrieval with more resilient fallback handling across different PowerPoint configurations

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Project	Deployment	Actions	Updated (UTC)
handout-powerpoint-addin	Ready	Preview, Comment	Apr 11, 2026 0:16am

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5c5d88a0-0118-4dd9-be0c-3a514259c0b0

📥 Commits

Reviewing files that changed from the base of the PR and between e6d855b and bff7ad0.

📒 Files selected for processing (1)

• apps/web/src/lib/powerpoint/officeBridge.ts

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📝 Walkthrough

Walkthrough

Modified the PowerPoint Office Bridge's slide detection and initialization flow. Added online/offline detection via isOnline(), replaced the primary slide-info retrieval strategy to use Office.context.document.getSelectedDataAsync, introduced getSlideCount() and powerPointRunGetSlide() helper functions, and removed the legacy legacyGetSlideInfo() function with conditional fallback handling.

Changes

Cohort / File(s)

Summary

Office Bridge Slide Detection Refactor apps/web/src/lib/powerpoint/officeBridge.ts

Added isOnline() function for platform detection. Restructured getCurrentSlideInfo() to prioritize Office.context.document.getSelectedDataAsync over PowerPoint.run. Introduced getSlideCount() helper using getSlideCountAsync with fallback to slideNumber. Added powerPointRunGetSlide() as Desktop-only fallback. Removed legacyGetSlideInfo() function. Updated initialization comments and clarified window blur/focus handler rationale.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• [codex] Fix PowerPoint slide sync detection #21: Modifies slide-detection logic in getCurrentSlideInfo() affecting slide-number computation strategy.
• Fix PowerPoint slide detection #20: Modifies slide-detection logic and selection-change handling in the PowerPoint Office Bridge with changes to polling behavior.

Poem

🐰 A bridge rebuilt with Online care,
Detecting desktops floating in the air,
When slides need finding, API knows the way—
Fallbacks and helpers save the day! ✨

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/office-init-timing

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[greptile-apps]

Greptile Summary

This PR fixes slide detection for PowerPoint Online by promoting getSelectedDataAsync(CoercionType.SlideRange) to the primary strategy and demoting PowerPoint.run() + getSelectedSlides() to a Desktop-only fallback. The motivation is correct — getSelectedSlides() is unreliable in Online and has been confirmed to return slide 1 regardless of actual selection.

Key changes:

• getSelectedDataAsync(SlideRange) is now the primary slide-detection method across all platforms.
• PowerPoint.run() + getSelectedSlides() is now skipped in Online via an isOnline() guard and used only as a Desktop fallback.
• The DocumentSelectionChanged handler fires immediately (no debounce) so the slide is read while focus is still active.
• A 500 ms polling loop and window blur/focus listeners supplement the event-based approach.

Critical issue found:

• The comment on line 186 claims slides[0].index is 0-based, but Microsoft's own documentation explicitly states it is 1-based. The + 1 on that line causes every reported slide number to be off by one — undermining the primary strategy this PR introduces.

Minor issues:

• Office.context.document.url can return an empty string in some Online environments; ?? \"Praesentation\" won't catch it.
• initOfficeBridge has no guard against being called twice, risking duplicate event handlers and redundant poll timers.

Confidence Score: 2/5

Not safe to merge as-is — the primary detection path introduced in this PR reports slide numbers that are consistently off by one on every platform.

The fix's intent is correct and the architectural restructuring (promoting getSelectedDataAsync to primary, guarding the Desktop fallback) is sound. However, the core implementation contains a critical off-by-one error: the index property from SlideRange is 1-based per Microsoft's own documentation, but the code treats it as 0-based and adds 1. This means the primary strategy — the central fix for PowerPoint Online — will always report the wrong slide number (e.g., slide 2 shows as slide 3), which breaks the user-facing feature this PR is meant to fix. The single-character fix is trivial, but the bug must be corrected before merging.

apps/web/src/lib/powerpoint/officeBridge.ts — specifically line 186-187 (off-by-one on slide index)

Important Files Changed

Filename	Overview
apps/web/src/lib/powerpoint/officeBridge.ts	Reworks slide detection strategy for PowerPoint Online — correct intent, but the primary path has a critical off-by-one error: slides[0].index from getSelectedDataAsync(SlideRange) is 1-based per MS docs, so adding +1 always reports one slide too high.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[syncCurrentSlide called
via poll / event / blur] --> B[getCurrentSlideInfo]
    B --> C{isInitialized &&
isOfficeAvailable?}
    C -- No --> D[resolve null]
    C -- Yes --> E[getSelectedDataAsync
SlideRange PRIMARY]
    E --> F{status !== Failed
&& slides.length > 0?}
    F -- Yes --> G["slideNumber = slides[0].index + 1
⚠️ BUG: index is 1-based,
should NOT add 1"]
    G --> H[getSlideCountAsync]
    H --> I[resolve OfficeSlideInfo]
    F -- No --> J{isOnline?}
    J -- Yes / API missing --> D
    J -- No --> K[powerPointRunGetSlide
Desktop fallback]
    K --> L[PowerPoint.run +
getSelectedSlides]
    L --> M[id-based indexOf lookup
then idx + 1]
    M --> I

Loading

Comments Outside Diff (2)

1. apps/web/src/lib/powerpoint/officeBridge.ts, line 170 (link)

   Fallback title may silently drop file extension check

   Office.context.document.url can return an empty string ("") on some Office Online environments (not just null/undefined). The nullish coalescing ?? "Praesentation" only catches null/undefined, so an empty string "" would flow through split, pop, and replace and ultimately produce an empty presentationTitle. Consider guarding against falsy values:

   

2. apps/web/src/lib/powerpoint/officeBridge.ts, line 127-130 (link)

   startPolling can create a timer leak if called multiple times

   startPolling clears any existing pollTimer before starting a new one, which prevents double-polling. However, initOfficeBridge can be called multiple times (it doesn't short-circuit when isInitialized is already true). A second call would re-start polling via startPolling() and also re-register the DocumentSelectionChanged and ActiveViewChanged handlers. Consider guarding at the top of initOfficeBridge:

   Or ensure destroyOfficeBridge is always called before re-initializing.

   

_{Reviews (1): Last reviewed commit: "fix: prioritize getSelectedDataAsync for..." | Re-trigger Greptile}

[greptile-apps]

slides[0].index is 1-based, not 0-based — slide number is off by 1

The code comment says "index is 0-based" and adds + 1, but the Microsoft Office.js documentation explicitly states:

"The index value of the slide is the 1-based value the user sees beside the slide in the thumbnails pane."

So for slide 3, slides[0].index returns 3, and 3 + 1 = 4 — one slide ahead of the actual position. This means the primary detection strategy (which is supposed to fix the PowerPoint Online bug) will always report the wrong slide number on every platform.

Suggested change

	const slideNumber = slides[0].index + 1; // index is 0-based
	getSlideCount(presentationTitle, slideNumber, resolve);
	const slideNumber = slides[0].index; // index is 1-based