Brightness

Brightness sets the screen brightness for the app's own window, and puts it back. It is for the screens that have a genuine reason to change it - a boarding pass, a QR code - not for a system setting.

The app's own brightness only. The system brightness is a global setting an app can leave changed after it is gone, and needs a permission on Android, so reaching for it is a decision to make deliberately against Expo's own API rather than a convenience this offers.

Install

npx expo install expo-brightness

import { Brightness } from '@ng-native/expo/brightness';

The smallest useful example

import { Component, DestroyRef, inject } from '@angular/core';
import { Brightness } from '@ng-native/expo/brightness';

@Component({
  selector: 'app-boarding-pass',
  template: `<text>Show this at the gate</text>`,
})
export class BoardingPass {
  private readonly brightness = inject(Brightness);

  constructor() {
    const restore = this.brightness.set(1);
    inject(DestroyRef).onDestroy(restore);
  }
}

What it does

level - a signal, nought to one. Starts at 1, since that is what a screen already shows before anything asks the platform.
set(level) - clamps to 0..1, applies it, and returns the function that restores the brightness the system had before. Always use the returned function rather than calling restore() separately: an app that leaves the screen at full brightness after showing a boarding pass is one the user experiences as a battery fault, not a bug they can name.
restore() - what the returned function calls. Available directly if a screen needs to put the brightness back without waiting for teardown.

Without the module installed

level stays at 1. set() and restore() do nothing and do not throw.

Reference

Brightnessservice@ng-native/expo

import { Brightness } from '@ng-native/expo';

Methods

set(level: number): () => void

Set it, and return the function that puts it back.