Files
tolaria/src/lib/themeMode.ts
2026-05-05 15:00:24 +02:00

106 lines
3.6 KiB
TypeScript

import { APP_STORAGE_KEYS, LEGACY_APP_STORAGE_KEYS } from '../constants/appStorage'
export const THEME_MODE_STORAGE_KEY = APP_STORAGE_KEYS.theme
export const LEGACY_THEME_MODE_STORAGE_KEY = LEGACY_APP_STORAGE_KEYS.theme
export const DEFAULT_THEME_MODE = 'light'
export const SYSTEM_THEME_MODE = 'system'
export const SYSTEM_THEME_MEDIA_QUERY = '(prefers-color-scheme: dark)'
const RESOLVED_THEME_MODES = new Set(['light', 'dark'])
const THEME_MODES = new Set([...RESOLVED_THEME_MODES, SYSTEM_THEME_MODE])
export type ResolvedThemeMode = 'light' | 'dark'
export type ThemeMode = ResolvedThemeMode | typeof SYSTEM_THEME_MODE
type ThemeStorage = Pick<Storage, 'getItem' | 'setItem'>
type ThemeDocument = Pick<Document, 'documentElement'>
type ThemeMatchMedia = Window['matchMedia']
export function normalizeThemeMode(value: unknown): ThemeMode | null {
return typeof value === 'string' && THEME_MODES.has(value) ? value as ThemeMode : null
}
export function normalizeResolvedThemeMode(value: unknown): ResolvedThemeMode | null {
const mode = normalizeThemeMode(value)
return mode === 'light' || mode === 'dark' ? mode : null
}
function resolveMatchMedia(matchMedia?: ThemeMatchMedia): ThemeMatchMedia | null {
if (matchMedia) return matchMedia
if (typeof window === 'undefined' || typeof window.matchMedia !== 'function') return null
return window.matchMedia.bind(window)
}
export function resolveSystemThemeMode(matchMedia?: ThemeMatchMedia): ResolvedThemeMode {
const resolvedMatchMedia = resolveMatchMedia(matchMedia)
if (!resolvedMatchMedia) return DEFAULT_THEME_MODE
try {
return resolvedMatchMedia(SYSTEM_THEME_MEDIA_QUERY).matches ? 'dark' : 'light'
} catch {
return DEFAULT_THEME_MODE
}
}
export function resolveThemeMode(value: unknown, matchMedia?: ThemeMatchMedia): ResolvedThemeMode {
const mode = normalizeThemeMode(value)
if (mode === SYSTEM_THEME_MODE) return resolveSystemThemeMode(matchMedia)
return mode ?? DEFAULT_THEME_MODE
}
function safeGetThemeMode(storage: ThemeStorage, key: string): ThemeMode | null {
try {
return normalizeThemeMode(storage.getItem(key))
} catch {
return null
}
}
function safeSetThemeMode(storage: ThemeStorage, key: string, mode: ThemeMode): void {
try {
storage.setItem(key, mode)
} catch {
// Storage can be unavailable in restricted browser contexts.
}
}
export function readStoredThemeMode(storage: ThemeStorage): ThemeMode | null {
const storedMode = safeGetThemeMode(storage, THEME_MODE_STORAGE_KEY)
if (storedMode) return storedMode
const legacyMode = safeGetThemeMode(storage, LEGACY_THEME_MODE_STORAGE_KEY)
if (!legacyMode) return null
safeSetThemeMode(storage, THEME_MODE_STORAGE_KEY, legacyMode)
return legacyMode
}
export function writeStoredThemeMode(storage: ThemeStorage, mode: ThemeMode): void {
safeSetThemeMode(storage, THEME_MODE_STORAGE_KEY, mode)
}
export function applyThemeModeToDocument(documentObject: ThemeDocument, mode: ResolvedThemeMode): void {
const root = documentObject.documentElement
root.setAttribute('data-theme', mode)
root.classList.toggle('dark', mode === 'dark')
}
export function applyThemeSelectionToDocument(
documentObject: ThemeDocument,
mode: ThemeMode,
matchMedia?: ThemeMatchMedia,
): ResolvedThemeMode {
const resolvedMode = resolveThemeMode(mode, matchMedia)
applyThemeModeToDocument(documentObject, resolvedMode)
return resolvedMode
}
export function applyStoredThemeMode(
documentObject: ThemeDocument,
storage: ThemeStorage,
matchMedia?: ThemeMatchMedia,
): ResolvedThemeMode {
const mode = readStoredThemeMode(storage) ?? DEFAULT_THEME_MODE
return applyThemeSelectionToDocument(documentObject, mode, matchMedia)
}