test(fetcher): cover JSON parsing error catch block

- Add test case for when error response JSON parsing fails
- Ensures the catch block fallback to default error message is covered
- Now at 77 total tests with complete line coverage
- Fixes missing coverage on line 59 in src/api/fetcher.ts

This should finally achieve true 100% coverage on Codecov! 🎯

Author: marklearst

CHANGELOG.md

@@ -19,7 +19,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ### Chores
 
-- **ci**: Achieved complete 100% test coverage across all 76 tests for optimal Codecov reporting
+- **ci**: Achieved complete 100% test coverage across all 78 tests for optimal Codecov reporting
 
 ## 1.4.4 (2024-12-19)
 

README.md

@@ -31,7 +31,7 @@ Built for the modern web, this library provides a suite of hooks to fetch, manag
 
 ## 🧱 Architecture Highlights
 
-✅ **100% Test Coverage** - Comprehensive test suite with 76 tests covering all hooks, utilities, and edge cases via Vitest
+✅ **100% Test Coverage** - Comprehensive test suite with 78 tests covering all hooks, utilities, and edge cases via Vitest
 ✅ **Consistent Error Handling** - Standardized error propagation with clear messages from the Figma API
 ✅ **Strictly Typed APIs** - Modern TypeScript best practices with full type inference and autocompletion
 ✅ **Predictable Hook Signatures** - Consistent, composable patterns designed for safe React integrations

tests/api/fetcher.test.ts

@@ -1,48 +1,69 @@
-import { describe, it, expect, vi } from 'vitest';
-import { fetcher } from '../../src/api/fetcher';
+import { describe, it, expect, vi } from 'vitest'
+import { fetcher } from '../../src/api/fetcher'
 
-const DUMMY_URL = 'https://api.example.com/test';
-const DUMMY_TOKEN = 'dummy-token';
+const DUMMY_URL = 'https://api.example.com/test'
+const DUMMY_TOKEN = 'dummy-token'
 
 // Helper to mock fetch
-function mockFetch(response: Partial<Response> & { json?: () => any }, ok = true) {
+function mockFetch(
+  response: Partial<Response> & { json?: () => any },
+  ok = true
+) {
   global.fetch = vi.fn().mockResolvedValue({
     ok,
     json: response.json || (() => Promise.resolve(response)),
     ...response,
-  }) as any;
+  }) as any
 }
 
 describe('fetcher', () => {
   afterEach(() => {
-    vi.resetAllMocks();
-  });
+    vi.resetAllMocks()
+  })
 
   it('throws if token is missing', async () => {
-    await expect(fetcher(DUMMY_URL, ''))
-      .rejects.toThrow(/token/i);
-  });
+    await expect(fetcher(DUMMY_URL, '')).rejects.toThrow(/token/i)
+  })
 
   it('returns JSON on success', async () => {
-    const data = { foo: 'bar' };
-    mockFetch({ json: () => Promise.resolve(data) });
-    const result = await fetcher(DUMMY_URL, DUMMY_TOKEN);
-    expect(result).toEqual(data);
-    expect(global.fetch).toHaveBeenCalledWith(DUMMY_URL, expect.objectContaining({
-      headers: expect.objectContaining({
-        'X-FIGMA-TOKEN': DUMMY_TOKEN,
-        'Content-Type': 'application/json',
-      }),
-    }));
-  });
+    const data = { foo: 'bar' }
+    mockFetch({ json: () => Promise.resolve(data) })
+    const result = await fetcher(DUMMY_URL, DUMMY_TOKEN)
+    expect(result).toEqual(data)
+    expect(global.fetch).toHaveBeenCalledWith(
+      DUMMY_URL,
+      expect.objectContaining({
+        headers: expect.objectContaining({
+          'X-FIGMA-TOKEN': DUMMY_TOKEN,
+          'Content-Type': 'application/json',
+        }),
+      })
+    )
+  })
+
+  it('uses the fallback json method when one is not provided', async () => {
+    // This object is compatible with `Partial<Response>`
+    const responseData = { status: 200, statusText: 'OK' }
+    // Call mockFetch without a `json` property to test the fallback path
+    mockFetch(responseData)
+    const result = await fetcher(DUMMY_URL, DUMMY_TOKEN)
+    // The fallback should resolve with the entire response object
+    expect(result).toEqual(responseData)
+  })
 
   it('throws with error message if response is not ok and error message exists', async () => {
-    mockFetch({ json: () => Promise.resolve({ message: 'fail!' }) }, false);
-    await expect(fetcher(DUMMY_URL, DUMMY_TOKEN)).rejects.toThrow('fail!');
-  });
+    mockFetch({ json: () => Promise.resolve({ message: 'fail!' }) }, false)
+    await expect(fetcher(DUMMY_URL, DUMMY_TOKEN)).rejects.toThrow('fail!')
+  })
 
   it('throws with fallback error if response is not ok and no message', async () => {
-    mockFetch({ json: () => Promise.resolve({}) }, false);
-    await expect(fetcher(DUMMY_URL, DUMMY_TOKEN)).rejects.toThrow(/fetch/i);
-  });
-});
+    mockFetch({ json: () => Promise.resolve({}) }, false)
+    await expect(fetcher(DUMMY_URL, DUMMY_TOKEN)).rejects.toThrow(/fetch/i)
+  })
+
+  it('throws with fallback error if response is not ok and JSON parsing fails', async () => {
+    // Mock a response that fails JSON parsing
+    mockFetch({ json: () => Promise.reject(new Error('Invalid JSON')) }, false)
+    await expect(fetcher(DUMMY_URL, DUMMY_TOKEN)).rejects.toThrow(/fetch/i)
+  })
+})