refactor: ES6+ modernization + 2 bugfixes

- var→const/let, function→arrow/class across all 13 JS files
- Timer: prototype→class with ES6 getters
- plan days: IIFE→Array.from declarative generation
- storage/plan: unified formatDate via util.js
- Bugfix: getPlanDay now filters by planId (plan switch accuracy)
- Bugfix: getTodayRecord searches all months (cross-month boundary)
- WXML/WXSS unchanged; public API unchanged

utils/theme.js

@@ -1,4 +1,4 @@
-var THEMES = [
+const THEMES = [
   {
     id: 'orange',
     name: '活力橙',
@@ -41,25 +41,23 @@ var THEMES = [
   }
 ]
 
-var DEFAULT_THEME_ID = 'orange'
-var THEME_KEY = 'app_theme'
-var _lastNavColor = ''
-var _navColorTimer = null
+const DEFAULT_THEME_ID = 'orange'
+const THEME_KEY = 'app_theme'
+let _lastNavColor = ''
+let _navColorTimer = null
 
-function getThemeById(id) {
-  return THEMES.find(function (t) { return t.id === id }) || THEMES[0]
-}
+const getThemeById = (id) => THEMES.find(t => t.id === id) || THEMES[0]
 
-function getCurrentTheme() {
-  var id = wx.getStorageSync(THEME_KEY) || DEFAULT_THEME_ID
+const getCurrentTheme = () => {
+  const id = wx.getStorageSync(THEME_KEY) || DEFAULT_THEME_ID
   return getThemeById(id)
 }
 
-function _setNavBarColor(primary) {
+const _setNavBarColor = (primary) => {
   if (_lastNavColor === primary) return
   _lastNavColor = primary
   if (_navColorTimer) clearTimeout(_navColorTimer)
-  _navColorTimer = setTimeout(function () {
+  _navColorTimer = setTimeout(() => {
     try {
       wx.setNavigationBarColor({
         frontColor: '#ffffff',
@@ -69,35 +67,35 @@ function _setNavBarColor(primary) {
   }, 50)
 }
 
-function setTheme(id) {
+const setTheme = (id) => {
   wx.setStorageSync(THEME_KEY, id)
-  var theme = getThemeById(id)
+  const theme = getThemeById(id)
   _setNavBarColor(theme.primary)
-  var app = getApp()
+  const app = getApp()
   if (app && app.globalData) app.globalData.theme = theme
   return theme
 }
 
-function applyThemeToPage(self) {
-  var theme = getCurrentTheme()
+const applyThemeToPage = (self) => {
+  const theme = getCurrentTheme()
   self.setData({
-    theme: theme,
-    themeStyle: '--primary:' + theme.primary + ';--primary-light:' + theme.primaryLight + ';--primary-bg:' + theme.primaryBg + ';--primary-rgb:' + theme.primaryRgb + ';'
+    theme,
+    themeStyle: `--primary:${theme.primary};--primary-light:${theme.primaryLight};--primary-bg:${theme.primaryBg};--primary-rgb:${theme.primaryRgb};`
   })
   _setNavBarColor(theme.primary)
 }
 
-function getThemeStyle(theme) {
-  var t = theme || getCurrentTheme()
-  return '--primary:' + t.primary + ';--primary-light:' + t.primaryLight + ';--primary-bg:' + t.primaryBg + ';--primary-rgb:' + t.primaryRgb + ';'
+const getThemeStyle = (theme) => {
+  const t = theme || getCurrentTheme()
+  return `--primary:${t.primary};--primary-light:${t.primaryLight};--primary-bg:${t.primaryBg};--primary-rgb:${t.primaryRgb};`
 }
 
 module.exports = {
-  THEMES: THEMES,
-  DEFAULT_THEME_ID: DEFAULT_THEME_ID,
-  getThemeById: getThemeById,
-  getCurrentTheme: getCurrentTheme,
-  setTheme: setTheme,
-  applyThemeToPage: applyThemeToPage,
-  getThemeStyle: getThemeStyle
+  THEMES,
+  DEFAULT_THEME_ID,
+  getThemeById,
+  getCurrentTheme,
+  setTheme,
+  applyThemeToPage,
+  getThemeStyle
 }