Add dark mode (#554)

src/redux/dark-mode/methods.ts

@@ -0,0 +1,45 @@
+import { store } from '..'
+import { DarkModeConfig, DarkModeConfigActionType, SetDarkModeConfigAction } from './types'
+
+export const setDarkMode = (darkMode: boolean): void => {
+  const action: SetDarkModeConfigAction = {
+    type: DarkModeConfigActionType.SET_DARK_MODE,
+    darkMode: darkMode
+  }
+  store.dispatch(action)
+}
+
+export const saveToLocalStorage = (darkModeConfig: DarkModeConfig): void => {
+  try {
+    window.localStorage.setItem('nightMode', String(darkModeConfig.darkMode))
+  } catch (e) {
+    console.error('Saving dark-mode setting to local storage failed: ', e)
+  }
+}
+
+export const loadFromLocalStorage = (): DarkModeConfig | undefined => {
+  try {
+    const storedValue = window.localStorage.getItem('nightMode')
+    if (!storedValue) {
+      return undefined
+    }
+    return {
+      darkMode: storedValue === 'true'
+    }
+  } catch (e) {
+    console.error('Loading dark-mode setting from local storage failed: ', e)
+    return undefined
+  }
+}
+
+export const determineDarkModeBrowserSetting = (): DarkModeConfig | undefined => {
+  try {
+    const mediaQueryResult = window.matchMedia('(prefers-color-scheme: dark)').matches
+    return {
+      darkMode: mediaQueryResult
+    }
+  } catch (e) {
+    console.error('Can not determine dark-mode setting from browser: ', e)
+    return undefined
+  }
+}