Brightness

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 puts back what was there before: the level an earlier set() still holds, such as the screen underneath a pushed one, or the system's own brightness once nothing does. 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() - puts the system's brightness back at once, whatever is still set. Available directly if a screen needs to put the brightness back without waiting for teardown.

Without the module

On iOS and Android, a missing expo-brightness - never installed, or installed without the app being rebuilt since - throws a MissingModuleError when the service first reaches for it. Its message names the module and the commands that fix it; see Using a module.

On the web, and in a test that provides no fake, level stays at 1. set() and restore() do nothing and do not throw.

Reference