move CRUD operations to helpers

helpers/fetch.ts

@@ -0,0 +1,40 @@
+import { ValidationError } from './validationError'
+
+const DEFAULT_FETCH_OPTIONS = {
+  method: 'GET',
+  mode: 'cors' as RequestMode,
+  cache: 'no-cache' as RequestCache,
+  credentials: 'same-origin' as RequestCredentials,
+  headers: {
+    'Content-Type': 'application/json',
+  },
+  referrerPolicy: 'no-referrer' as ReferrerPolicy,
+}
+
+export type FetchOptions = Omit<RequestInit, 'body'> & {
+  body?: object
+}
+
+export default async function fetchJSON(
+  url: string,
+  options: FetchOptions = {}
+) {
+  const response = await fetch(url, {
+    ...DEFAULT_FETCH_OPTIONS,
+    ...options,
+    body: !!options.body ? JSON.stringify(options.body) : undefined,
+  })
+
+  if (response.status === 400) {
+    const error = await response.json()
+    throw new ValidationError(error.errors)
+  }
+
+  if (!response.ok) {
+    throw Error(
+      'Sorry, konnte nicht gespeichert werden. Bitte versuch es später nochmal!'
+    )
+  }
+
+  return response.json()
+}