Mode Watcher

Simple utilities to manage light & dark mode in your Angular app.

Installation

Make sure you are using Angular 16 or greater.

npm install ngx-mode-watcher

Usage

Add provideModeWatcher() to your app config app.config.ts file.

import { provideModeWatcher } from 'ngx-mode-watcher';

export const appConfig: ApplicationConfig = {
  providers: [
    // ...
    provideModeWatcher(),
  ],
};

The provider will automatically detect the user's preferences and apply/remove the "dark" class, along with the corresponding color-scheme style attribute to the html element.

ModeWatcher will automatically track operating system preferences and apply these if no user preference is set. If you wish to disable this behavior, set the track config to false:

provideModeWatcher({
  track: false,
});

ModeWatcher can also be configured with a default mode instead of automatically detecting the user's preference.

To set a default mode, use the defaultMode config:

provideModeWatcher({
  defaultMode: 'dark',
});

ModeWatcher can manage the theme-color meta tag for you.

To enable this, set the themeColor config to your preferred colors:

provideModeWatcher({
  themeColor: { dark: 'black', light: 'white' },
});

ModeWatcherService

To manage the mode of your application, you can inject the ModeWatcherService.

import { ModeWatcherService } from './mode-watcher.service';

@Component({
  //...
})
export class MyComp {
  private readonly modeWatcher = inject(ModeWatcherService);
}

API

toggleMode

A function that toggles the current mode.

modeWatcher = inject(ModeWatcherService);

<button (click)="modeWatcher.toggleMode()">Toggle Mode</button>

setMode

A function that sets the current mode. It accepts a string with the value "light", "dark" or "system".

modeWatcher = inject(ModeWatcherService);

<button (click)="modeWatcher.setMode('light')">Set Light Mode</button>
<button (click)="modeWatcher.setMode('dark')">Set Dark Mode</button>

resetMode

A function that resets the mode to system preferences.

modeWatcher = inject(ModeWatcherService);

<button (click)="modeWatcher.resetMode()">System</button>

mode

A signal that contains the current mode. It can be "light" or "dark" or undefined if evaluated on the server.

modeWatcher = inject(ModeWatcherService);
handleModeChange() {
    if (modeWatcher.mode() === 'light') {
        modeWatcher.setMode('dark');
    } else {
        modeWatcher.setMode('light');
    }
}

<button (click)="handleModeChange()">{{ modeWatcher.mode() }}</button>

userPrefersMode

A signal that represents the user's mode preference. It can be "light", "dark" or "system".

systemPrefersMode

A signal that represents the operating system's mode preference. It can be "light", "dark" or undefined if evaluated on the server. Will automatically track changes to the operating system's mode preference unless this is disabled with the track config which takes a boolean.

Inspiration & credits

This project is an Angular port of svecosystem's mode-watcher.