https://ukpressonline.co.uk/assets/scripts/theme-toggle.js?t=1781370153213

1/*
2 * Copyright (c) 2023 Lemur Software Ltd.
3 */
4
5/*!
6 * Color mode toggler for Bootstrap's docs (https://getbootstrap.com/)
7 * Copyright 2011-2022 The Bootstrap Authors
8 * Licensed under the Creative Commons Attribution 3.0 Unported License.
9 */
10
11(() => {
12    'use strict'
13
14    let storedTheme = localStorage.getItem('theme');
15
16    const getPreferredTheme = () => {
17        if (storedTheme) {
18            return storedTheme;
19        }
20
21        return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
22    }
23
24    const setTheme = function (theme) {
25        if (theme === 'auto' && window.matchMedia('(prefers-color-scheme: dark)').matches) {
26            document.documentElement.setAttribute('data-bs-theme', 'dark');
27        } else {
28            document.documentElement.setAttribute('data-bs-theme', theme);
29        }
30    }
31
32    setTheme(getPreferredTheme());
33
34    const showActiveTheme = theme => {
35        const activeThemeIcon = document.querySelector('.theme-icon-active');
36        const btnToActive = document.querySelector(`[data-bs-theme-value="${theme}"]`);
37        const classOfActiveSpan = btnToActive.querySelector('span:first-of-type').getAttribute('class');
38
39        document.querySelectorAll('[data-bs-theme-value]')
40            .forEach(element => {
41                element.classList.remove('active');
42            });
43        btnToActive.classList.add('active');
44        activeThemeIcon.setAttribute('class', classOfActiveSpan + ' theme-icon-active');
45    }
46
47    window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', () => {
48        if (storedTheme !== 'light' || storedTheme !== 'dark') {
49            setTheme(getPreferredTheme());
50        }
51    })
52
53    window.addEventListener('DOMContentLoaded', () => {
54        showActiveTheme(getPreferredTheme());
55
56        document.querySelectorAll('[data-bs-theme-value]')
57            .forEach(toggle => {
58                toggle.addEventListener('click', () => {
59                    const theme = toggle.getAttribute('data-bs-theme-value');
60                    localStorage.setItem('theme', theme);
61                    storedTheme = theme;
62                    setTheme(theme);
63                    showActiveTheme(theme);
64                })
65            });
66    });
67})()