Tarun Sharma

T
Tarun Sharma
4 posts
Testing a component that uses WebSockets, without a real server
A component that talks to a REST API is easy to test. You mock the HTTP call, resolve it with fixture data, assert on the render. A component that talks to a WebSocket is a different animal, and most
Sep 16, 20264 min read6
Why does React call your component function twice in development?
If you have added a console.log at the top of a component in a fresh Create React App or Next.js project, you have probably noticed it fires twice on the first render. Nothing is broken. This is Stric
Sep 9, 20263 min read
The virtual DOM doesn't skip rendering. It skips writing to the DOM.
"The virtual DOM skips re-rendering unchanged parts" is one of those explanations that gets repeated so often it starts to sound obviously true. It's not quite right, and the gap between what it actua
Aug 18, 20263 min read3
The closures question that trips up almost every React interview
If there's one JavaScript question that shows up in almost every frontend interview in some form, it's this one: for (var i = 0; i < 3; i++) { setTimeout(() => console.log(i)); } What does this log
Aug 14, 20263 min read4