https://www.codeslog.com/en/tags/frontend/ Recent content in Frontend on Codeslog https://www.codeslog.com/images/default-cover.png?v=20260114T1436 https://www.codeslog.com/images/default-cover.png?v=20260114T1436 Hugo -- 0.150.0 en-US Tue, 14 Jul 2026 23:52:00 +0900 https://www.codeslog.com/en/posts/javascript-nullish-coalescing/ Tue, 14 Jul 2026 23:52:00 +0900 https://www.codeslog.com/en/posts/javascript-nullish-coalescing/ The decisive difference between the nullish coalescing operator (??) and || — it's why 0 and empty strings get swallowed by defaults. Falsy traps, ??= assignment, optional chaining combos, and why mixing the two throws a SyntaxError. https://www.codeslog.com/en/posts/frontend-testing-msw/ Tue, 14 Jul 2026 01:05:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-msw/ Calling a real API in tests is slow and unstable. Isolate the network layer with MSW (Mock Service Worker) and simulate success and failure responses at will — a real reception desk for your requests. https://www.codeslog.com/en/posts/frontend-testing-user-event/ Mon, 13 Jul 2026 23:39:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-user-event/ Reproduce real user interactions — typing, clicking, selecting — with user-event, and test forms and state changes from render to result, the way a user would actually drive them. https://www.codeslog.com/en/posts/frontend-testing-testing-library/ Fri, 10 Jul 2026 01:27:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-testing-library/ React Testing Library's core philosophy: test like a user. Learn the query priority built around getByRole, and how testing behavior instead of implementation makes tests survive refactoring. https://www.codeslog.com/en/posts/frontend-testing-test-doubles/ Fri, 10 Jul 2026 00:44:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-test-doubles/ mock, stub, spy, fake… the confusing test-double vocabulary, sorted out. Cover all three with a single Vitest vi.fn() (Jest is nearly identical), and learn the one rule for how much to fake. https://www.codeslog.com/en/posts/typescript-7-native-compiler/ Thu, 09 Jul 2026 23:05:00 +0900 https://www.codeslog.com/en/posts/typescript-7-native-compiler/ TypeScript 7 has shipped, reborn in Go. Real benchmarks (VSCode: 125s to 10s), the new strict-by-default config, side-by-side installs with 6.x — everything you need to decide whether to switch today. https://www.codeslog.com/en/posts/frontend-testing-async/ Wed, 08 Jul 2026 00:27:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-async/ Promises, setTimeout, and the failure cases. Test frontend async code reliably with Vitest's resolves/rejects matchers and fake timers — no real waiting, no flakiness. https://www.codeslog.com/en/posts/frontend-testing-unit-basics/ Mon, 06 Jul 2026 00:20:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-unit-basics/ The sturdiest foundation there is: unit tests. Learn how to test pure functions, hunt edge cases, and structure every test with the AAA (Arrange-Act-Assert) pattern — with real-world examples. https://www.codeslog.com/en/posts/frontend-testing-strategy-coverage/ Sat, 04 Jul 2026 22:34:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-strategy-coverage/ Are more tests always better? A practical guide to picking what deserves tests first — and to reading coverage numbers without being fooled by them. https://www.codeslog.com/en/posts/frontend-testing-glossary/ Sat, 04 Jul 2026 22:30:00 +0900 https://www.codeslog.com/en/posts/frontend-testing-glossary/ From unit tests to flaky, fixtures, and MCP — every term in the Frontend Testing, Done Right series, explained for beginners and ordered the way you'll meet them. Bookmark this page and come back whenever a word looks unfamiliar. https://www.codeslog.com/en/posts/frontend-testing-why-now/ Fri, 03 Jul 2026 16:33:17 +0900 https://www.codeslog.com/en/posts/frontend-testing-why-now/ The faster AI writes code, the more testing matters. In this opener of the Frontend Testing, Done Right series, we cover what tests really give you, pyramid vs. trophy strategy, and the full curriculum ahead.