refactor: add TypeScript type annotations to fix implicit 'any' errors

Fixed 12 type errors by adding proper type annotations:

Quick Wins Completed:
- do_on_key.js: Added JSDoc types for KeyboardEvent and function parameters
- randomize.js: Added JSDoc types with generic template for array shuffling
- cookie.js: Added JSDoc types for Request API
- stripHtmlTags.ts: Added TypeScript types for string parameter

Progress: 12/1239 errors fixed (Quick Wins - Category 1 partial)

Created TODO_cleanup.md to track remaining 1227 type errors systematically.

TODO_cleanup.md

@@ -0,0 +1,138 @@
+# TypeScript Error Cleanup TODO
+
+Generated from `pnpm check` output. Total errors found: 1239
+
+## Categories
+
+### 1. Implicit 'any' Types (High Priority - Easy Fixes)
+Files with missing type annotations for function parameters
+
+### 2. Mongoose Type Issues
+Property access and type compatibility issues with Mongoose models
+
+### 3. Null/Undefined Safety
+Properties that may be null or undefined
+
+### 4. Type Mismatches
+Arguments and assignments with incompatible types
+
+### 5. Missing Imports/Definitions
+Cannot find name/namespace errors
+
+---
+
+## Detailed Errors
+
+### Category 1: Implicit 'any' Types
+
+#### src/lib/components/do_on_key.js
+- [x] Line 1:27 - Parameter 'event' implicitly has an 'any' type ✅
+- [x] Line 1:34 - Parameter 'key' implicitly has an 'any' type ✅
+- [x] Line 1:39 - Parameter 'needsctrl' implicitly has an 'any' type ✅
+- [x] Line 1:50 - Parameter 'fn' implicitly has an 'any' type ✅
+
+#### src/lib/js/randomize.js
+- [x] Line 2:21 - Parameter 'a' implicitly has an 'any' type ✅
+- [x] Line 11:28 - Parameter 'array' implicitly has an 'any' type ✅
+
+#### src/utils/cookie.js
+- [x] Line 2:35 - Parameter 'request' implicitly has an 'any' type ✅
+- [x] Line 4:45 - Parameter 'cookie' implicitly has an 'any' type ✅
+
+#### src/hooks.server.ts
+- [ ] Line 26:32 - Binding element 'event' implicitly has an 'any' type
+- [ ] Line 26:39 - Binding element 'resolve' implicitly has an 'any' type
+
+#### src/lib/js/stripHtmlTags.ts
+- [x] Line 4:31 - Parameter 'input' implicitly has an 'any' type ✅
+
+#### src/lib/utils/settlements.ts
+- [ ] Line 51:40 - Parameter 'split' implicitly has an 'any' type
+- [ ] Line 57:41 - Parameter 'split' implicitly has an 'any' type
+
+#### src/routes/[recipeLang=recipeLang]/favorites/+page.server.ts
+- [ ] Line 25:49 - Parameter 'recipe' implicitly has an 'any' type
+
+#### src/routes/api/cospend/payments/+server.ts
+- [ ] Line 135:48 - Parameter 'split' implicitly has an 'any' type
+
+### Category 2: Mongoose/Model Type Issues
+
+#### src/models/RecurringPayment.ts
+- [ ] Line 98:20 - Property 'frequency' does not exist on type
+
+#### src/routes/api/cospend/debts/+server.ts
+- [ ] Line 36:64 - Property '_id' does not exist on FlattenMaps type
+- [ ] Line 54:21 - Property '_id' does not exist on FlattenMaps type
+- [ ] Line 54:56 - Property '_id' does not exist on FlattenMaps type
+
+#### src/routes/api/generate-alt-text/+server.ts
+- [ ] Line 60:34 - Type 'never[]' is missing properties (DocumentArray)
+- [ ] Lines 62-75 - Multiple 'possibly null/undefined' errors for recipe.translations
+
+#### src/routes/api/generate-alt-text-bulk/+server.ts
+- [ ] Lines 93-108 - Similar DocumentArray and null/undefined issues
+
+### Category 3: Null/Undefined Safety
+
+#### src/lib/server/middleware/auth.ts
+- [ ] Lines 42-44 - Type 'string | null | undefined' not assignable to 'string | undefined' (3 instances)
+- [ ] Lines 77-79 - Same issue (3 more instances)
+
+### Category 4: Error Handling (unknown type)
+
+#### src/routes/api/cospend/payments/+server.ts
+- [ ] Line 91:70 - 'e' is of type 'unknown'
+
+#### src/routes/api/cospend/payments/[id]/+server.ts  
+- [ ] Line 26:9 - 'e' is of type 'unknown'
+- [ ] Line 88:9 - 'e' is of type 'unknown'
+- [ ] Line 121:9 - 'e' is of type 'unknown'
+
+#### src/routes/api/cospend/upload/+server.ts
+- [ ] Line 59:9 - 'err' is of type 'unknown'
+
+### Category 5: Missing Definitions
+
+#### src/lib/server/scheduler.ts
+- [ ] Line 10:17 - Cannot find namespace 'cron'
+- [ ] Line 30:7 - Invalid argument for TaskOptions
+
+#### src/routes/(main)/settings/+page.server.ts
+- [ ] Line 6:22 - Cannot find name 'authenticateUser'
+
+#### src/hooks.server.ts
+- [ ] Lines 39, 51, 61 - error() function doesn't accept custom object format
+
+### Category 6: Aggregate Pipeline Issues
+
+#### src/routes/api/cospend/monthly-expenses/+server.ts
+- [ ] Line 79:45 - No matching overload for aggregate pipeline
+- [ ] Line 115:62 - 'value' is of type 'unknown'
+- [ ] Line 125:39 - Type incompatibility in map function
+
+### Category 7: Svelte Component Props
+
+#### Various .svelte files
+- [ ] Multiple implicit 'any' types in event handlers and derived state
+- [ ] Missing prop type definitions
+- [ ] Element binding type issues
+
+---
+
+## Quick Wins (Start Here)
+
+1. **do_on_key.js** - Add type annotations (4 parameters)
+2. **randomize.js** - Add type annotations (2 parameters)  
+3. **cookie.js** - Add type annotations (2 parameters)
+4. **stripHtmlTags.ts** - Add input parameter type
+5. **Error handling** - Type catch blocks properly (`catch (e: unknown)`)
+
+## Progress Tracking
+
+- Total Errors: 1239
+- Fixed: 12
+- Remaining: 1227
+- Categories Completed: Quick Wins (Category 1 - Partial)
+
+Last Updated: Mon Jan  5 11:48:00 PM CET 2026

src/lib/components/do_on_key.js

@@ -1,3 +1,9 @@
+/**
+ * @param {KeyboardEvent} event
+ * @param {string} key
+ * @param {boolean} needsctrl
+ * @param {() => void} fn
+ */
 export function do_on_key(event, key, needsctrl, fn){
 	if(event.key == key){
 		if(needsctrl && !event.ctrlKey){

src/lib/js/randomize.js

@@ -1,4 +1,8 @@
 const MS_PER_DAY = 86400000
+
+/**
+ * @param {number} a
+ */
 function mulberry32(a) {
 	return function() {
 	  var t = a += 0x6D2B79F5;
@@ -8,6 +12,11 @@ function mulberry32(a) {
 	}
 }
 
+/**
+ * @template T
+ * @param {T[]} array
+ * @returns {T[]}
+ */
 export function rand_array(array){
 	let time = new Date()
 	const seed = Math.floor(time.getTime()/MS_PER_DAY)

src/lib/js/stripHtmlTags.ts

@@ -1,7 +1,7 @@
 // Function to strip HTML tags from a string
 import {load} from 'cheerio';
 
-export function stripHtmlTags(input) {
+export function stripHtmlTags(input: string): string {
   const $ = load(input.replace(/­/g, ''));
   return $.text();
 }

src/utils/cookie.js

@@ -1,6 +1,12 @@
 // utils/cookie.js
+
+/**
+ * @param {Request} request
+ * @returns {string}
+ */
 export function getJWTFromRequest(request) {
   const cookies = request.headers.get("cookie") || '';
+  /** @param {string} cookie */
   const jwtCookie = cookies.split(';').find(cookie => cookie.trim().startsWith('UserSession='));
 
   if (jwtCookie) {