# Empty Link Fixer

A Chrome extension (Manifest V3) that automatically fixes empty `<a>` tags on a
website you configure at build time — links with an `href` but no visible
content get the href inserted as their text:

```html
<!-- before -->
<a href="/docs/api"></a>

<!-- after -->
<a href="/docs/api">/docs/api</a>
```

It also works on **dynamically rendered sites** (SPAs, virtual DOM, infinite
scroll, web components): a content script watches the live DOM and fills empty
links as soon as they appear.

## Install

1. Open `chrome://extensions`, enable **Developer mode**.
2. Click **Load unpacked** and select this directory.
3. Visit the configured site — empty links are filled automatically.

## Configuration

Edit **`config.js`** before loading the extension (no runtime UI), then reload
the extension in `chrome://extensions`:

```js
globalThis.LINK_FIX_CONFIG = {
  hosts: ["example.com"],     // website(s), matched against location.hostname
  includeSubdomains: true,    // also www., docs., app. example.com
  rescanIntervalMs: 3000,     // safety-net re-scan; 0 disables it
  debug: false,               // verbose console logging
};
```

`hosts: ["*"]` fixes every site (debugging only). For local testing, serve a
page over HTTP and set `hosts: ["localhost"]` (hostname only — the port is
ignored).

## How it works

1. **Initial pass** — empty anchors already on the page are fixed at startup.
2. **`MutationObserver`** over the whole document reacts to nodes added/removed,
   text emptied in place, and `href` attributes appearing later.
3. **Open shadow roots** (web components) are watched recursively.
4. **Periodic re-scan** catches changes with no observable DOM mutation.

An anchor is touched only if it has a real `href` (not `#` or
`javascript:`/`data:`/`vbscript:`), no visible text, and no media content
(`img`, `svg`, `canvas`, …). Links with text or icons are left alone, as are
`contenteditable` regions.

## Layout

```
manifest.json   MV3 declaration (injects the content script on all sites)
config.js       site configuration — the only file you normally edit
content.js      the fixer (initial scan + MutationObserver + shadow DOM)
tests/smoke.mjs smoke test:  npm install --no-save jsdom && node tests/smoke.mjs
```