dashy/src/utils/ThemeHelper.js

73 lines
2.4 KiB
JavaScript

import ErrorHandler from '@/utils/ErrorHandler';
import { getTheme, getCustomColors } from '@/utils/ConfigHelpers';
import { mainCssVars } from '@/utils/defaults';
/* Returns users current theme */
export const GetTheme = () => getTheme();
/* Gets user custom color preferences for current theme, and applies to DOM */
export const ApplyCustomVariables = (theme) => {
mainCssVars.forEach((vName) => { document.documentElement.style.removeProperty(`--${vName}`); });
const themeColors = getCustomColors()[theme];
if (themeColors) {
Object.keys(themeColors).forEach((customVar) => {
document.documentElement.style.setProperty(`--${customVar}`, themeColors[customVar]);
});
}
};
/* Sets the theme, by updating data-theme attribute on the html tag */
export const ApplyLocalTheme = (newTheme) => {
const htmlTag = document.getElementsByTagName('html')[0];
if (htmlTag.hasAttribute('data-theme')) htmlTag.removeAttribute('data-theme');
htmlTag.setAttribute('data-theme', newTheme);
};
/**
* A function for pre-loading, and easy switching of external stylesheets
* External CSS is preloaded to avoid FOUC
*/
export const LoadExternalTheme = function th() {
/* Preload selected external theme */
const preloadTheme = (href) => {
const link = document.createElement('link');
link.rel = 'stylesheet';
link.type = 'text/css';
link.href = href;
document.head.appendChild(link);
return new Promise((resolve, reject) => {
link.onload = e => {
const { sheet } = e.target;
sheet.disabled = true;
resolve(sheet);
};
link.onerror = reject;
});
};
/* Check theme is selected, and it exists */
const checkTheme = (themes, name) => {
if ((!name) || (name !== 'custom' && !themes[name])) {
ErrorHandler(`Theme: '${name || '[not selected]'}' does not exist.`);
return false;
}
return true;
};
/* Disable all but selected theme */
const selectTheme = (themes, name) => {
if (checkTheme(themes, name)) {
const t = themes; // To avoid ESLint complaining about mutating a param
Object.keys(themes).forEach(n => { t[n].disabled = (n !== name); });
}
};
const themes = {};
return {
add(name, href) { return preloadTheme(href).then(s => { themes[name] = s; }); },
set theme(name) { selectTheme(themes, name); },
get theme() { return Object.keys(themes).find(n => !themes[n].disabled); },
};
};