When the control overlay (and its live time readout) is briefly absent,
the old fallback recomputed the timeline from the raw blob-relative
video.currentTime via a cached scale/start. Disney recreates the <video>
element on some play/pause transitions, which resets currentTime, so that
math produced a wildly wrong time ("loses the time" after a pause).
The native clock advances 1:1 with real playback, so instead anchor the
last live UI position to video.currentTime and extrapolate by the elapsed
native delta. If the delta is negative or implausibly large (element
recreated / seek), freeze at the last known position rather than emitting
a garbage time.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Development Scripts
This directory contains utility scripts for the KoalaSync development workflow.
build-extension.cjs
The primary build tool for KoalaSync. This Node.js script automates two critical tasks:
- Protocol Synchronization: Copies the "Single Source of Truth" constants (
shared/constants.js) and the domain blacklist (shared/blacklist.js) from the root/shareddirectory into theextension/shared/directory. - Content Script Injection: Injects protocol constants directly into
content.jsusing marker-based replacement. This is necessary becausecontent.jsexecutes synchronously and cannot use ES module imports. - Artifact Generation: Compiles the extension into browser-specific bundles for Chrome and Firefox, located in the
dist/directory.
Usage
From the repository root, run:
node scripts/build-extension.cjs
Why this script exists
KoalaSync uses Vanilla JS in the extension to maintain zero runtime dependencies and maximum privacy. Since we don't use a bundler (like Webpack or Vite) inside the extension, this script serves as our lightweight "pre-build" step to ensure that the protocol constants remain synchronized between the extension and the relay server.
Content Injection Markers
The build script uses marker comments in content.js to locate and replace constant blocks:
| Marker Pair | Injected Value | Source |
|---|---|---|
SHARED_EVENTS_INJECT_START / END |
The full EVENTS object |
shared/constants.js |
SHARED_HEARTBEAT_INJECT_START / END |
HEARTBEAT_INTERVAL value |
shared/constants.js |
⚠️ Do NOT remove or modify these marker comments in
content.js. They are required for the build script to function. If the markers are missing, the build will fail with a clear error message.