# Share as QR

A small Firefox extension that turns the current tab's URL into a scannable QR
code, so you can hand a page off to a phone (or another machine) without
typing.

## What you see

Click the toolbar icon while you're on any normal web page. A small popup
opens showing:

- a black-and-white QR code (~280 px square) encoding the current URL,
- the URL itself in muted text below the QR,
- a **Copy URL** button that puts the URL on your clipboard.

The popup honours `prefers-color-scheme`, so dark-mode users get a dark
chrome around a white QR (the QR itself must stay light-on-dark for cameras
to read it).

On browser-internal pages (`about:`, `chrome:`, `view-source:`,
`moz-extension:`, `data:`, `javascript:`, `resource:`) the popup shows a
*"This page can't be shared"* message instead of attempting to encode the
URL. URLs longer than the largest QR version (~2.9 KB) get a *"too long to
encode"* message.

## Supported Firefox versions

`manifest.json` sets `strict_min_version: 142.0`. That floor exists because
the manifest declares
`browser_specific_settings.gecko.data_collection_permissions`, which was
introduced in Firefox 140 (desktop) / 142 (Android).

## Develop

This project uses [bun](https://bun.sh) as both the script runner and the
bundler. `popup/popup.js` imports the vendored QR library; `bun build`
inlines it into a single minified ESM file under `dist/`. Firefox loads the
extension from `dist/`, never from the source tree directly.

There are no runtime dependencies and no `node_modules` to install — `bunx`
pulls `web-ext` on demand. The first run is slow (download + cache); later
runs are fast.

```sh
bun run build      # bundle popup.js + assets into dist/
bun run lint       # build + web-ext lint  (must be 0 errors / 0 warnings)
bun run package    # build + produce a signable .zip in web-ext-artifacts/
bun run start      # build + launch Firefox with the extension loaded
```

### Loading the extension manually

After `bun run build`:

1. Open `about:debugging#/runtime/this-firefox` in Firefox 142+.
2. Click **Load Temporary Add-on…** and pick **`dist/manifest.json`**.
3. The QR icon appears in the toolbar. Click it on any normal page.

The temporary install is wiped when Firefox restarts; reload the same way
during dev. For a more persistent dev loop use `bun run start`, which
launches Firefox with the extension already loaded and auto-reloads on file
changes.

### Build flow

```
popup/popup.js  ──┐
                  │  bun build (esm, minified, browser target)
vendor/qrcode.js ─┘            │
                               ▼
                       dist/popup/popup.js    (~23 KB)

manifest.json, popup/{html,css}, icons/, vendor/LICENSE.qrcode-generator
        └──── copied verbatim into dist/ ───────►  dist/

web-ext operates on dist/ only, so the packaged zip contains exactly what
the build emitted — never AGENTS.md, .dogcats/, scripts/, or other repo-only
files.
```

## Privacy

The extension makes **no network requests**. The QR code is generated
locally in the popup using the bundled `vendor/qrcode.js` library. The
`browser_specific_settings.gecko.data_collection_permissions` field in the
manifest declares `"none"` accordingly, which surfaces during AMO review and
in the install prompt.

Permissions used (both are the minimum the feature needs):

| Permission       | Why                                              |
| ---------------- | ------------------------------------------------ |
| `activeTab`      | Read the active tab's URL when the popup opens.  |
| `clipboardWrite` | Implement the **Copy URL** button.               |

## Publishing to AMO

`bun run package` produces a deterministic `web-ext-artifacts/share_as_qr-<ver>.zip`
from a clean checkout. The zip contains only the files in `dist/`:

```
dist/
  manifest.json
  LICENSE.qrcode-generator
  icons/icon.svg
  popup/popup.html
  popup/popup.css
  popup/popup.js         (bundled, minified)
```

For AMO source-code review, point the reviewer at this repository and the
pinned upstream commit of `vendor/qrcode.js` documented below.

## Third-party code

- `vendor/qrcode.js` — [kazuhikoarase/qrcode-generator](https://github.com/kazuhikoarase/qrcode-generator),
  pinned to commit `83b7e8fe3fddd3b0368dbafd6ce56995bd25e3c8`. MIT licensed;
  full license text in `vendor/LICENSE.qrcode-generator` (also copied into
  `dist/` so it ships with every build).

## License

This project is MIT-licensed; see [LICENSE](LICENSE).

## Project layout

```
manifest.json          MV3 manifest
popup/                 Toolbar popup source (HTML/CSS/JS)
vendor/qrcode.js       Bundled QR encoder (MIT, vendored, imported by popup.js)
icons/icon.svg         Toolbar icon (single SVG, used at every size)
scripts/build.mjs      Bun build + asset copy → dist/
web-ext-config.cjs     Tells web-ext to operate on dist/
dist/                  Build output (gitignored). What ships.
```