What front end interviews test

Front end interviews differ from general programming interviews and preparing for the wrong one is a common waste of months.

What they typically contain. JavaScript fundamentals, asked in detail. Practical CSS and layout. Building a small component, frequently live. Questions about the browser: how a page loads, what happens on a request, rendering. Framework specific questions. And how you approach a problem.

What they contain less of. Heavy algorithm work, which appears at large international companies and rarely in local product companies or agencies. Do not spend three months on graph algorithms for a role that will ask you to build a filterable list.

Find out the format first, by asking. A live coding exercise, a take home task, a systems discussion and a general conversation all need different preparation, and the question is entirely reasonable to ask.

The most common failure is weak JavaScript fundamentals behind framework familiarity. Somebody who has built several React applications and cannot explain closures, the event loop or how this is determined is extremely common and is identified within ten minutes.

The second is being unable to build something without a framework. Asked to build a component in plain JavaScript, somebody who only knows a framework is stuck, and interviewers ask this specifically because it separates the two.

So the preparation that pays is the language and the browser, not another framework.