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mirror of https://github.com/jakejarvis/jarv.is.git synced 2025-04-28 04:50:28 -04:00
jarv.is/assets/js/dark-mode.js

104 lines
3.5 KiB
JavaScript

/* jshint esversion: 6, indent: 2, browser: true, quotmark: single */
// inspired by https://codepen.io/kevinpowell/pen/EMdjOV
(function() {
'use strict';
// lightbulb toggle re-appears now that we know user has JS enabled
const toggle = document.querySelector('button#dark-mode-toggle');
toggle.style.visibility = 'visible';
// check for preset `dark_mode_pref` in localStorage
let pref = localStorage.getItem('dark_mode_pref');
// keep track of current state (light by default)
let dark = false;
// load utteranc.es with proper theme and dynamically switch it
let utterancesLoaded = false;
const setUtterancesTheme = function(theme) {
const container = document.querySelector('div#comments');
// don't do any of this if we're not on a page with comments enabled
if (container) {
if (!utterancesLoaded) {
const script = document.createElement('script');
script.type = 'text/javascript';
script.async = true;
script.defer = true;
script.src = 'https://utteranc.es/client.js';
script.crossOrigin = 'anonymous';
script.setAttribute('data-repo', '{{ .Site.Params.github | safeJS }}');
script.setAttribute('data-label', 'comments');
script.setAttribute('data-issue-term', 'og:title');
script.setAttribute('data-theme', theme);
container.appendChild(script);
utterancesLoaded = true;
} else {
const frame = document.querySelector('iframe.utterances-frame');
// be extra sure frame exists
if (frame) {
// https://github.com/utterance/utterances/blob/4d9823c6c4f9a58365f06e2aa76c51b8cf5d5478/src/configuration-component.ts#L160
frame.contentWindow.postMessage({
type: 'set-theme',
theme: theme
}, 'https://utteranc.es');
}
}
}
};
const activateDarkMode = function() {
document.body.classList.remove('light');
document.body.classList.add('dark');
dark = true;
setUtterancesTheme('github-dark');
};
const activateLightMode = function() {
document.body.classList.remove('dark');
document.body.classList.add('light');
dark = false;
setUtterancesTheme('github-light');
};
// if user already explicitly toggled in the past, restore their preference.
if (pref === 'true') activateDarkMode();
if (pref === 'false') activateLightMode();
// user has never clicked the button, so go by their OS preference until/if they do so
if (!pref) {
// check for OS dark mode setting and switch accordingly
// https://gist.github.com/Gioni06/eb5b28343bcf5793a70f6703004cf333#file-darkmode-js-L47
if (window.matchMedia('(prefers-color-scheme: dark)').matches)
activateDarkMode();
else
activateLightMode();
// real-time switching if supported by OS/browser
// TODO: stop listening when the parent condition becomes false,
// right now these keep listening even if pref is set.
window.matchMedia('(prefers-color-scheme: dark)').addListener(function(e) { if (e.matches) activateDarkMode(); });
window.matchMedia('(prefers-color-scheme: light)').addListener(function(e) { if (e.matches) activateLightMode(); });
}
// handle lightbulb click
toggle.addEventListener('click', function() {
// switch to the opposite theme & save preference in local storage
if (!dark) {
activateDarkMode();
localStorage.setItem('dark_mode_pref', 'true');
} else {
activateLightMode();
localStorage.setItem('dark_mode_pref', 'false');
}
}, true);
})();