further implementing service page (#3)

src/lib/utils.ts

@@ -1,6 +1,44 @@
 import { clsx, type ClassValue } from "clsx"
 import { twMerge } from "tailwind-merge"
+import { z } from "zod"
 
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs))
 }
+
+const emptyStringToUndefined = z.literal('').transform(() => undefined);
+
+export function asOptionalField<T extends z.ZodTypeAny>(schema: T) {
+  return schema.optional().or(emptyStringToUndefined);
+}
+
+export const conv = {
+  recordToStr: (rec: Record<string, boolean>) => {
+    const arr: string[] = [];
+    for (const key in rec) {
+      arr.push(key);
+    }
+
+    return arr.join(',');
+  },
+  strToRecord: (str: string) => {
+    const arr = str.split(',');
+    return arr.reduce((acc, num) => {
+      acc[num] = true;
+      return acc;
+    }, {} as Record<string, boolean>);
+  },
+  arrToStr: <T>(arr: T[]) => {
+    return arr.join(',');
+  },
+  strToArr: (str: string) => {
+    return str.split(',');
+  },
+  recordToArr: <T>(rec: Record<string, T>) => {
+    const arr: T[] = [];
+    for (const val of Object.values(rec)) {
+      arr.push(val);
+    }
+    return arr;
+  },
+}