Move credentials check.

src/Options.ts

@@ -31,4 +31,30 @@ type Options = Xor<
   apiEndpoint?: string;
 } & Pick<AxiosRequestConfig, 'adapter' | 'proxy' | 'socketPath' | 'timeout'>;
 
+const falsyDescriptions = new Map<any, string>([
+  [undefined, 'undefined'],
+  [null, 'null'],
+  ['', 'an empty string'],
+]);
+
+/**
+ * Returns an error message (string) similar to `"Parameter "×" is null."` if a property with the passed key exists in
+ * the passed options object, or `null` if said property does not exist.
+ */
+function describeFalsyOption(options: Options, key: keyof Options) {
+  if (key in options == false) {
+    return null;
+  }
+  return `Parameter "${key}" is ${falsyDescriptions.get(options[key]) ?? options[key]}.`;
+};
+
+/**
+ * Throws a `TypeError` if the passed options object does not contain an `apiKey` or an `accessToken`.
+ */
+export function checkCredentials(options: Options) {
+  if (!options.apiKey && !options.accessToken) {
+    throw new TypeError(describeFalsyOption(options, 'apiKey') ?? describeFalsyOption(options, 'accessToken') ?? 'Missing parameter "apiKey" or "accessToken".');
+  }
+}
+
 export default Options;

src/createMollieClient.ts

@@ -3,8 +3,8 @@ import { version as libraryVersion } from '../package.json';
 import caCertificates from './cacert.pem';
 import NetworkClient from './communication/NetworkClient';
 import TransformingNetworkClient, { Transformers } from './communication/TransformingNetworkClient';
+import { checkCredentials } from './Options';
 import type Options from './Options';
-import { run } from 'ruply';
 
 // Transformers
 import { transform as transformPayment } from './data/payments/Payment';
@@ -59,25 +59,6 @@ import SettlementsBinder from './binders/settlements/SettlementsBinder';
 import SubscriptionsBinder from './binders/subscriptions/SubscriptionsBinder';
 import SubscriptionPaymentsBinder from './binders/subscriptions/payments/SubscriptionPaymentsBinder';
 
-/**
- * Returns an error message (string) similar to `"Parameter "×" is null."` if a property with the passed key exists in
- * the passed object, or `null` if said property does not exist.
- */
-const describeFalsyOption = run(
-  new Map([
-    [undefined, 'undefined'],
-    [null, 'null'],
-    ['', 'an empty string'],
-  ]) as Map<any, string>,
-  descriptions =>
-    function describeFalsyOption<O extends Record<string, unknown>>(object: O, key: keyof O & string) {
-      if (key in object == false) {
-        return null;
-      }
-      return `Parameter "${key}" is ${descriptions.get(object[key]) ?? object[key]}.`;
-    },
-);
-
 /**
  * Create Mollie client.
  * @since 2.0.0
@@ -90,9 +71,7 @@ export default function createMollieClient(options: Options) {
     );
   }
 
-  if (!options.apiKey && !options.accessToken) {
-    throw new TypeError(describeFalsyOption(options, 'apiKey') ?? describeFalsyOption(options, 'accessToken') ?? 'Missing parameter "apiKey" or "accessToken".');
-  }
+  checkCredentials(options);
 
   const networkClient = new NetworkClient({ ...options, libraryVersion, nodeVersion: process.version, caCertificates });