expo-flashlight

Expo module to control the device torch (flashlight): turn it on/off and adjust its brightness.

• iOS — continuous brightness via AVCaptureDevice.setTorchModeOn(level:).
• Android — on/off via CameraManager.setTorchMode; adjustable brightness on Android 13+ (API 33) via turnOnTorchWithStrengthLevel, with automatic on/off fallback on older devices.
• Web — reports the torch as unavailable (control is not supported).

Installation

npx expo install expo-flashlight

This is a native module, so it requires a development build — it does not run in Expo Go.

Usage

import Flashlight from 'expo-flashlight';

if (Flashlight.isAvailable()) {
  Flashlight.enable();           // turn on (last/full brightness)
  Flashlight.setBrightness(0.5); // 50% brightness (0..1)
  Flashlight.toggle();           // flip on/off, returns the new state

  if (Flashlight.isOn) {
    Flashlight.disable();        // turn off
  }
}

Reacting to state changes

import Flashlight, { ExpoFlashlightModule } from 'expo-flashlight';
import { useEvent } from 'expo';

function TorchStatus() {
  const state = useEvent(ExpoFlashlightModule, 'onTorchStateChanged');
  // state?.enabled, state?.brightness
}

Or imperatively:

const sub = Flashlight.addListener(({ enabled, brightness }) => {
  console.log({ enabled, brightness });
});
// later
sub.remove();

API

| Member | Type | Description | | --- | --- | --- | | isAvailable() | boolean | Whether the device has a controllable torch. | | isBrightnessControlAvailable() | boolean | Whether brightness can be adjusted (always on iOS with a torch; Android 13+ only). | | enable(brightness?) | void | Turn the torch on. Optional 0..1 brightness. | | disable() | void | Turn the torch off. | | toggle() | boolean | Toggle the torch; returns the new on/off state. | | set(on) | void | Set the torch on or off. | | setBrightness(level) | void | Set brightness 0..1. 0 turns the torch off. | | getBrightness() | number | Current brightness 0..1 (0 when off). | | isOn / isOff | boolean (getter) | Whether the torch is currently on/off. | | isEnabled() | boolean | Method form of isOn. | | addListener(cb) | EventSubscription | Subscribe to { enabled, brightness } changes. |

Brightness on Android

Below Android 13 the torch is on/off only, so setBrightness(level) turns the torch on at full brightness for any level > 0. On Android 13+ the normalized 0..1 value is mapped to the device's discrete strength steps. Use isBrightnessControlAvailable() to detect support.

Development

This package uses Bun as its package manager.

bun install      # install dependencies
bun run build    # compile src/ -> build/
bun run lint     # eslint
bun run test     # run the Vitest suite once
bun run test:watch

Unit tests live in src/__tests__/ and use Vitest. The native module is mocked, so the tests cover the JavaScript wrapper logic (brightness clamping, delegation, getters, event subscription) without a device.

License

MIT © Aziz Becha