Noprocrast

A browser extension that limits time spent on distracting websites, modelled on Hacker News's noprocrast feature.

Each blocked site gets a configurable visit window (maxvisit minutes). Once that window is used up, the tab redirects to a block page and stays blocked for a cooldown period (minaway minutes). A manual override is available but only resets the timer — it does not disable the system.

How it works

• Navigation to a tracked domain records a visit start time.
• Navigation away (or closing the tab) flushes elapsed time into a session counter.
• When the session counter reaches maxvisit, the site is blocked and a cooldown alarm is scheduled via browser.alarms.
• After minaway minutes the alarm fires and the site is automatically unblocked.
• All timing is event-driven — no background polling, no content scripts.

Configuration

Global defaults (configurable in Settings):

maxvisit = 20 minutes minaway = 180 minutes

Per-site overrides for maxvisit and/or minaway can be set from the Settings page. Subdomains match automatically: adding reddit.com also covers old.reddit.com.

Browser support

Chrome 120+ (MV3, service worker) Firefox 128+ (MV3, background scripts)

The extension source is identical across browsers. A build step generates a browser-specific manifest.json from manifest.base.json, which is the shared source of truth. Chrome requires a plain service worker entry; Firefox additionally needs a background.scripts fallback.

Installation (unpacked)

Chrome:

1. Clone the repository.
2. Run: npm install && npm run build:chrome
3. Open chrome://extensions and enable Developer mode (toggle, top-right).
4. Click "Load unpacked" and select the repo directory.
5. Pin the extension via the puzzle-piece icon in the toolbar.

To reload after code changes: run npm run build:chrome, then click the refresh icon on the extension card.

Firefox:

1. Clone the repository.
2. Run: npm install && npm run build:firefox
3. Open about:debugging and click "This Firefox" in the left sidebar.
4. Click "Load Temporary Add-on..." and select manifest.json from the repo.

The extension stays loaded until Firefox restarts. To reload after code changes: run npm run build:firefox, then click the Reload button on about:debugging.

Development

npm run build:chrome Generate manifest.json for Chrome npm run build:firefox Generate manifest.json for Firefox npm run lint Run ESLint (must pass with zero warnings or errors)

manifest.json is generated and not tracked by git. Always run the appropriate build command before loading or reloading the extension in a browser.

File structure

manifest.base.json        Shared manifest source (no background field)
scripts/
  build-manifest.js       Generates manifest.json for a given browser
shared/
  browser-api.js          Unified api export (only file referencing chrome/browser)
  storage.js              Storage read/write helpers
  domain.js               domainMatches(), extractHostname()
  limits.js               getEffectiveLimits()
background/
  service-worker.js       All event listeners and timer logic
pages/
  blocked.*               Block page with timed override
popup/
  popup.*                 Status view with quick add-site
options/
  options.*               Settings page

License

See LICENSE.