Frontend Concepts That Separate Junior from Senior Developers 👀

Frontend Concepts That Separate Junior from Senior Developers 👀 Hydration Hydration happens when server-rendered HTML becomes interactive in the browser. Without it, your page loads but buttons, forms, and state won't work. This is a core concept in frameworks like Next.js. Debouncing Debouncing delays a function until the user stops triggering it. For example, search inputs. Instead of making an API request on every keystroke, it waits, improving performance and reducing unnecessary calls. Memoization Memoization stores expensive computations so they don't run again unnecessarily. In React, this helps prevent useless re-renders and improves performance. Useful in large component trees. Event Bubbling Events in the DOM move upward from child to parent. If you click a button inside a div, both can receive the event unless stopped. Understanding this makes debugging interactions much easier. Reconciliation Reconciliation is how React compares old and new UI to update only what changed. This is why React apps feel fast. Understanding it helps you write better components. Code Splitting Instead of shipping your entire app at once, code splitting loads only what's needed. This improves load speed and user experience. Especially important in large applications. CSR vs SSR vs SSG Client-side rendering loads content in the browser. Server-side rendering generates it on the server. Static site generation builds it before users even visit. Knowing when to use each affects performance and SEO.