reverse-shell-generator/bootstrap-darkmode-master/theme.ts

class ThemeConfig {
    themeChangeHandlers: ((theme: string) => void)[] = [];

    loadTheme(): string | null {
        return localStorage.getItem('theme');
    }

    saveTheme(theme: string | null): void {
        if (theme === null) {
            localStorage.removeItem('theme');
        }
        else {
            localStorage.setItem('theme', theme)
        }
    }

    initTheme(): void {
        this.displayTheme(this.getTheme());
    }

    detectTheme(): string {
        return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
    }

    getTheme(): string {
        return this.loadTheme() || this.detectTheme();
    }

    setTheme(theme: string): void {
        this.saveTheme(theme);
        this.displayTheme(theme);
    }

    displayTheme(theme: string): void {
        document.body.setAttribute('data-theme', theme);
        for (let handler of this.themeChangeHandlers) {
            handler(theme);
        }
    }
}

function writeDarkSwitch(config: ThemeConfig) {
    document.write(`
<div class="custom-control custom-switch">
<input type="checkbox" class="custom-control-input" id="darkSwitch">
<label class="custom-control-label" for="darkSwitch">Dark Mode</label>
</div>
`);

    const darkSwitch = document.getElementById('darkSwitch') as HTMLInputElement;

    darkSwitch.checked = config.getTheme() === 'dark';
    darkSwitch.onchange = () => {
        config.setTheme(darkSwitch.checked ? 'dark' : 'light');
    };

    config.themeChangeHandlers.push(theme => darkSwitch.checked = theme === 'dark');

    return darkSwitch;
}