From c76a5d727f593725bbd75268d10b9c6228940d11 Mon Sep 17 00:00:00 2001
From: "Pimm \"de Chinchilla\" Hogeling" <pimmhogeling@gmail.com>
Date: Fri, 5 Jul 2024 15:59:41 +0200
Subject: [PATCH] Add a more helpful error to createMollieClient for missing
 credentials.

Previously, not setting apiKey or accessToken to an appropriate value would result in a generic error. With this change, an accidental empty string gives a distinct error from no value at all.
---
 src/createMollieClient.ts             | 22 +++++++++++++++++++++-
 tests/unit/createMollieClient.test.ts | 16 +++++++++++++---
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/src/createMollieClient.ts b/src/createMollieClient.ts
index 9e83a2ce..89e5775b 100644
--- a/src/createMollieClient.ts
+++ b/src/createMollieClient.ts
@@ -4,6 +4,7 @@ import caCertificates from './cacert.pem';
 import NetworkClient from './communication/NetworkClient';
 import TransformingNetworkClient, { Transformers } from './communication/TransformingNetworkClient';
 import type Options from './Options';
+import { run } from 'ruply';
 
 // Transformers
 import { transform as transformPayment } from './data/payments/Payment';
@@ -58,6 +59,25 @@ 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
@@ -71,7 +91,7 @@ export default function createMollieClient(options: Options) {
   }
 
   if (!options.apiKey && !options.accessToken) {
-    throw new TypeError('Missing parameter "apiKey" or "accessToken".');
+    throw new TypeError(describeFalsyOption(options, 'apiKey') ?? describeFalsyOption(options, 'accessToken') ?? 'Missing parameter "apiKey" or "accessToken".');
   }
 
   const networkClient = new NetworkClient({ ...options, libraryVersion, nodeVersion: process.version, caCertificates });
diff --git a/tests/unit/createMollieClient.test.ts b/tests/unit/createMollieClient.test.ts
index ee145d1f..6a40a37f 100644
--- a/tests/unit/createMollieClient.test.ts
+++ b/tests/unit/createMollieClient.test.ts
@@ -1,9 +1,19 @@
 import createMollieClient from '../..';
 
-describe('mollie', () => {
-  it('should fail when no api key is provided', () => {
+describe('createMollieClient', () => {
+  it('should fail when no credentials are provided', () => {
     // eslint-disable-next-line @typescript-eslint/ban-ts-ignore
     // @ts-ignore
-    expect(() => createMollieClient(undefined)).toThrowError(TypeError);
+    expect(() => createMollieClient({})).toThrow('Missing parameter "apiKey" or "accessToken".');
+  });
+
+  it('should throw a descriptive error when a apiKey is set to null', () => {
+    // eslint-disable-next-line @typescript-eslint/ban-ts-ignore
+    // @ts-ignore
+    expect(() => createMollieClient({ apiKey: null })).toThrow('Parameter "apiKey" is null.');
+  });
+
+  it('should throw a descriptive error when a apiKey is set to an empty string', () => {
+    expect(() => createMollieClient({ apiKey: '' })).toThrow('Parameter "apiKey" is an empty string.');
   });
 });