Component Testing in 2026, the Return of the Browser

React Advanced

React Advanced 2026

Guy Nesher

<p>Component tests started in real browsers with Karma: high fidelity, but slow feedback and painful config. Jest + JSDOM made tests fast and easy, but emulation can miss rendering, layout, and browser APIs.</p><p>Playwright and Vitest Browser Mode bring back browser-first testing with headless speed, parallel runs, and traces. We’ll compare the approaches and share migration tips for legacy code.</p>