prefer-promise-reject-errors lint error fixes (#1448)

* prefer-promise-reject-errors lint error fixes

* add unit tests for fetchSupportFrontendData function

* unnecessary if conditional check is removed

Author: AnastasiiaBalenko

eslint-suppressions.json

@@ -15,20 +15,6 @@
       "count": 1
     }
   },
-  "src/server/lib/fetchTickerData.ts": {
-    "@typescript-eslint/prefer-promise-reject-errors": {
-      "count": 3
-    },
-    "@typescript-eslint/no-unsafe-argument": {
-      "count": 2
-    },
-    "@typescript-eslint/no-unsafe-member-access": {
-      "count": 2
-    },
-    "@typescript-eslint/no-unnecessary-condition": {
-      "count": 1
-    }
-  },
   "src/server/middleware/errorHandling.ts": {
     "@typescript-eslint/no-unsafe-assignment": {
       "count": 1
@@ -114,14 +100,6 @@
       "count": 1
     }
   },
-  "src/server/utils/supportFrontend.ts": {
-    "@typescript-eslint/prefer-promise-reject-errors": {
-      "count": 3
-    },
-    "@typescript-eslint/no-unsafe-member-access": {
-      "count": 1
-    }
-  },
   "src/server/utils/valueReloader.ts": {
     "@typescript-eslint/no-floating-promises": {
       "count": 1

src/server/lib/fetchTickerData.ts

@@ -15,15 +15,15 @@ const tickerUrl = (stage: Stage, name: TickerName): string => {
 
 const checkForErrors = (response: Response): Promise<Response> => {
     if (!response.ok) {
-        return Promise.reject(
+        const error = new Error(
             response.statusText || `Ticker api call returned HTTP status ${response.status}`,
         );
+        return Promise.reject(error);
     }
     return Promise.resolve(response);
 };
 
-// eslint-disable-next-line @typescript-eslint/no-explicit-any -- JSON not yet parsed to a type.
-const parse = (json: any): Promise<TickerData> => {
+const parse = (json: { total: string; goal: string }): Promise<TickerData> => {
     const total = parseInt(json.total);
     const goal = parseInt(json.goal);
 
@@ -33,7 +33,8 @@ const parse = (json: any): Promise<TickerData> => {
             goal,
         });
     } else {
-        return Promise.reject(`Failed to parse ticker data: ${json}`);
+        const error = new Error(`Failed to parse ticker data: ${JSON.stringify(json)}`);
+        return Promise.reject(error);
     }
 };
 
@@ -44,8 +45,9 @@ const getTickerDataForTickerTypeFetcher =
             .then((response) => response.json())
             .then(parse)
             .catch((error) => {
-                logError(`Error fetching ${name} ticker data: ${error}`);
-                return Promise.reject(error);
+                const errorObj = error instanceof Error ? error : new Error(String(error));
+                logError(`Error fetching ${name} ticker data: ${errorObj.message}`);
+                return Promise.reject(errorObj);
             });
     };
 
@@ -61,9 +63,7 @@ export class TickerDataProvider {
 
     getTickerData(name: TickerName): TickerData | undefined {
         const provider = this.providers[name];
-        if (provider) {
-            return provider.get();
-        }
+        return provider.get();
     }
 
     addTickerDataToSettings(tickerSettings: TickerSettings): TickerSettings | undefined {

src/server/utils/supportFrontend.test.ts

@@ -0,0 +1,43 @@
+import { fetchSupportFrontendData } from './supportFrontend';
+
+describe('fetchSupportFrontendData', () => {
+    const originalFetch = global.fetch;
+
+    beforeAll(() => {
+        global.fetch = jest.fn();
+    });
+
+    afterAll(() => {
+        global.fetch = originalFetch;
+    });
+    it('should throw an error if no endpoint is provided', async () => {
+        await expect(fetchSupportFrontendData('')).rejects.toThrow('No endpoint value supplied');
+    });
+    it('should throw an error if fetch response is not ok', async () => {
+        (global.fetch as jest.Mock).mockResolvedValueOnce({
+            ok: false,
+            status: 404,
+        });
+        await expect(fetchSupportFrontendData('test-endpoint')).rejects.toThrow(
+            'HTTP error! Status: 404',
+        );
+    });
+
+    it('should return response text if fetch is successful', async () => {
+        const mockText = 'response data';
+        (global.fetch as jest.Mock).mockResolvedValueOnce({
+            ok: true,
+            text: jest.fn().mockResolvedValueOnce(mockText),
+        });
+        const data = await fetchSupportFrontendData('test-endpoint');
+        expect(data).toBe(mockText);
+    });
+
+    it('should throw an error if fetch fails', async () => {
+        const mockError = new Error('Network error');
+        (global.fetch as jest.Mock).mockRejectedValueOnce(mockError);
+        await expect(fetchSupportFrontendData('test-endpoint')).rejects.toThrow(
+            'Data fetch error: Error: Network error',
+        );
+    });
+});

src/server/utils/supportFrontend.ts

@@ -3,7 +3,7 @@ import { isProd } from '../lib/env';
 export const fetchSupportFrontendData = (endpoint: string): Promise<string> => {
     return new Promise((resolve, reject) => {
         if (!endpoint) {
-            reject('{"error": "No endpoint value supplied"}');
+            reject(new Error('No endpoint value supplied'));
         }
 
         const supportUrl = isProd
@@ -15,11 +15,11 @@ export const fetchSupportFrontendData = (endpoint: string): Promise<string> => {
         fetch(apiUrl)
             .then((packet) => {
                 if (!packet.ok) {
-                    reject(`{"error": "HTTP error! Status: ${packet.status}"}`);
+                    reject(new Error(`HTTP error! Status: ${packet.status}`));
                 }
                 return packet.text();
             })
             .then((res) => resolve(res))
-            .catch((err) => reject(`{"error": "Data fetch error: ${err.message}"}`));
+            .catch((err) => reject(new Error(`Data fetch error: ${String(err)}`)));
     });
 };