move CRUD operations to helpers

helpers/validationError.ts

@@ -0,0 +1,39 @@
+import { VALIDATION_ERRORS } from '../db/enums'
+
+interface ValidationErrors {
+  [key: string]: { properties: { message: string }; kind: string }
+}
+
+function getDefinedValidationMessage(kind: string) {
+  switch (kind) {
+    case VALIDATION_ERRORS.AT_LEAST_ONE_DAY_BOOKED:
+      return 'Mindestens ein angefragter Tag ist nicht mehr verfügbar'
+    default:
+      return null
+  }
+}
+
+export class ValidationError extends Error {
+  private errors: ValidationErrors
+
+  constructor(errors: ValidationErrors) {
+    super()
+
+    if (Error.captureStackTrace) {
+      Error.captureStackTrace(this, ValidationError)
+    }
+    this.name = this.constructor.name
+    this.errors = errors
+  }
+
+  get message() {
+    return Object.entries<{ properties: { message: string }; kind: string }>(
+      this.errors
+    )
+      .map(([_key, value]) => {
+        const validationMessage = getDefinedValidationMessage(value.kind)
+        return validationMessage || `${value?.properties?.message}`
+      })
+      .join(',')
+  }
+}