Battery Monitor

Native macOS battery monitor tray app with low-battery alerts, settings, and keyboard shortcut.

Supported Platforms

• macOS on Apple silicon (arm64, M1/M2+)
• Intel Macs are not supported

Features

• macOS tray app showing battery percentage with low-battery alerts
• Toggle notifications from tray or keyboard (Ctrl+Alt+N)
• Loop interval: 0 = single alert, >0 = repeating alerts
• Tray title/tooltip indicate status and next-alert countdown
• Settings: threshold (%), loop interval (s), launch at login, notify on AC
• Battery status via Electron powerMonitor with pmset fallback on macOS
• Robust error logging with global handlers
• Security policies: sandboxed, blocked window.open, denied navigation, isolated preload

Notes

This app focuses on tray-based battery monitoring and notifications using Electron-only APIs. Native daemon integration has been removed.

Notifications are controlled via the tray menu and keyboard shortcut, not via a master toggle in the settings panel. The only notification-related configuration in Settings is the loop interval (seconds) used for repeating alerts when the threshold is met.

Notification Loop Behavior:

• Interval = 0: A single notification is shown when the threshold is met; no repeat is scheduled.
• Interval > 0: Notifications repeat at the configured interval until disabled or the condition no longer holds.

Dynamic Interval Updates:

• Changing the loop interval in Settings immediately reconfigures the notification loop without restart.
• The existing loop is safely cleaned up and a new schedule starts with the updated interval.

Keyboard Shortcut:

• Press Ctrl+Alt+N to toggle notifications on/off. The tray title shows 🔔 when enabled and 🔕 when disabled.

Settings Overview:

• Notification threshold (%) — slider at top of Settings
• Loop interval (seconds) — integer 0–3600
• Launch at startup — macOS login item
• Notify when charging — deliver alerts even when on AC power

Assets:

• App icon: place assets/icon.icns and set in package.json build.mac.icon.
• Tray icon: assets/trayTemplate.png (monochrome template image, tinted by macOS).
  • Generate .icns from a base PNG using sips and iconutil:
    • mkdir -p assets/AppIcon.iconset
    • Resize with sips to standard sizes, then: iconutil -c icns assets/AppIcon.iconset -o assets/icon.icns

Develop

npm install
npm start

Build (Apple silicon)

npm run build

Test Notification

npm run test:notify -- 50

This triggers a notification if your battery is on battery power and <= 50%.

Unit Tests

npm run test:unit

Runs basic tests for interval clamping and single vs loop behavior.