NotifyAvailability

NotifyAvailability watches a webpage for you and posts a local notification when a piece of text appears on it. You pick a URL, the search text, and whether you care about presence or absence; the app re-checks about every 15 minutes in the background until you press Stop. The classic use case: get pinged when a movie booking site finally opens sales for your date.

Features

• Background watch — press Start Checking to schedule a periodic background job (~15-minute cadence) and Stop Checking to cancel it
• Found or absent — notifies when the search text shows up by default; the "Search Absence of Text" switch flips that so you hear about disappearance instead (useful for outage or delisting watches)
• Case-sensitive search — on by default; the switch turns it off
• Webpage type — Mobile, Desktop, or Tablet rendering. Desktop sends a desktop User-Agent on both the background fetch and the in-app preview
• Last Checked — timestamp shown as relative time ("5 minutes ago"), or "Never" before any check has run
• Live preview — while a watch is active, the page loads in an embedded WebView so you can eyeball what the checker sees
• Loading indicator — spins during the first check after Start
• URL validation — Start refuses URLs that lack the http:// / https:// prefix
• Auto-resume — if the app closes while a watch is running, the watch resumes on next launch

Tech Stack

Layer	Library
Framework	React Native 0.87 (React 19.2), TypeScript strict
Notifications	react-native-notify-kit 10.5
Background scheduling	react-native-background-fetch 4.4 (JobScheduler-backed periodic fetch on Android)
Persistence	@react-native-async-storage/async-storage 3.1
In-app browser	react-native-webview 14
Picker	@react-native-picker/picker 2.11
Tooling	Jest 29 + Testing Library, ESLint, Prettier

The 2019 version used react-native-push-notification and a JS timer (react-native-background-timer). Both are gone: notifications moved to notify-kit and scheduling moved to native background fetch.

Requirements

• Node.js >= 22.11.0 (enforced via engines in package.json)
• Yarn 1.x
• JDK 17 (Android builds)
• Android SDK set up for React Native 0.87

Getting Started

yarn install        # dependencies
yarn start          # Metro bundler
yarn android        # build and install on a connected device/emulator

Lint, types, tests

yarn lint
yarn typecheck
yarn test

CI runs all three on Node 22 for every push and pull request (.github/workflows/ci.yml).

Building an APK

cd android && ./gradlew assembleRelease

Release builds produce one APK per ABI (armeabi-v7a, x86, arm64-v8a, x86_64) instead of a single universal APK — roughly 20 MB each, and arm64-v8a covers most modern phones. Builds are signed in CI with a dedicated keystore supplied through four repository secrets (ANDROID_KEYSTORE_BASE64, ANDROID_KEYSTORE_PASSWORD, ANDROID_KEY_ALIAS, ANDROID_KEY_PASSWORD). When the secrets are absent, android-release.yml falls back to an unsigned debug-keystore artifact. The workflow cuts version releases on v* tags and republishes the rolling latest pre-release with fresh per-ABI APKs on every merge to master. To rotate the signing key: generate a new keystore and update the four secrets.

Architecture

src/
├── App.tsx                     Composition root: config state, URL validation,
│                               Start/Stop handlers, WebView preview
├── Styles.ts                   Shared StyleSheet
├── constants.ts                Desktop User-Agent string, web platform values
├── types.ts                    WatchConfig shape and defaults
├── utils.ts                    formatRelativeTime and escapeRegExp helpers
├── components/
│   ├── UrlInput.tsx            URL field (memoized)
│   ├── SearchInput.tsx         Search text field (memoized, forwards ref)
│   ├── SettingsSwitch.tsx      Labeled switch: case sensitivity, absence mode
│   └── PlatformPicker.tsx      Mobile/Desktop/Tablet picker
├── services/
│   ├── notificationService.ts  Channel setup and local notifications (notify-kit)
│   ├── checkService.ts         Fetches the page and searches for the text
│   └── watchScheduler.ts       startWatch / stopWatch / resumeWatchIfNeeded
│                               over react-native-background-fetch
└── storage/
    └── configStorage.ts        loadWatchConfig / saveWatchConfig over AsyncStorage

App.tsx loads the persisted config on launch, resumes a running watch if there was one, and wires the memoized components to saveWatchConfig. Services own everything native: notifications, page checks, and the periodic schedule.

Storage keys have not changed since the 2019 app (url, searchText, taskSet, webPlatformType, lastChecked, caseSensitiveSearch, searchAbsence, with yes/no values), so existing installs upgrade with zero migration.

Known Quirks

• Tablet behaves like Mobile — Tablet uses the same default User-Agent as Mobile; there is no tablet-specific one. Kept as-is to match the original app.
• Background cadence belongs to the OS — Android's job scheduler enforces a 15-minute minimum interval and batches jobs under Doze, so checks can land later than the nominal ~15 minutes.
• Notification permission prompt — the first Start triggers it. Notifications post to the channel id availability.
• iOS is a scaffold stub — never built (pod install has not been run); yarn ios exists in package.json but expect nothing from it.

Use Case

One use case: enter the URL of a movie booking website and get notified when it opens booking for a Cinema on the day you want.