Ask HN: How to prepare for a Front-end Developer interview?

In my experience, closures are a topic that always comes up. It is also important to know how to handle a closure inside of a for loop. I've been asked about "this" binding, coercion, and CSS specificity. I've had to solve problems that required me to know about how to use stacks, trees, and nested for loops. Other topics that have come up are how to architect an app, concurrency, memoization, building out and handling api endpoints, and pass by reference vs. pass by value.

You may not think databases are a front-end topic, but I have been asked about them on more than one occasion. Prepare to talk about sharding, natural primary keys, what your favorite database is and why, etc.

Something that has been extremely useful for me is to have a project that I've built myself to show and talk about during the interview. Although I have had one interview where I was asked to talk in detail about how I built some of my projects that are in my github, I like to respond to general technical questions while referencing something I've built. A lot of times the interviewer will then use my app as a starting point into a discussion for how I would scale it. Here's an example of an app I built quickly and have used for discussion in interviews: http://moviemap.xyz/ More here: http://valeriemettler.com/

Nice list here, but by no means exhaustive: https://github.com/h5bp/Front-end-Developer-Interview-Questi...

You should at least be familiar with the major front-end libraries and frameworks - React, Angular and Ember. You don't necessarily need to "know" them, but at least know about them.

You should be familiar with what ES6 is and what Babel does. These technologies probably won't be specific questions per se but if they come up and you can't speak about them, it'd be a red flag.

Even for a front-end developer you should have a basic knowledge of data structures like linked lists, binary trees, min/max heaps, depth/breadth first search, tries, recursion, hash tables, etc. These often come up in whiteboarding questions.

Practice whiteboarding on an actual whiteboard so you get used to writing code then practice on hackerrank so you get used to quickly writing code that actually compiles. Some companies only use whiteboards, others want your code to run.

Make sure you think of test cases for your problems. TDD in an interview is usually a good sign.

Usually knowing this stuff and having some sample code will usually get you through most of the interview. Knowing the specific things mentioned in other comments is useful, but I can't imagine not hiring someone because they didn't know some specific CSS selector or how to use flexbox.

Other tips - don't get visibly flustered, talk your way through problems. Stay postive about past employers. Good luck!

Aside from all the technical questions, don't underestimate the importance of knowing about the company you are applying to.

I've hired several developers over the last 10 years, and by the final round, there are often candidates with similar technical ability. The applicant that really understands the company they are applying to work for (the current state of their app, their competition, the direction you think they may need to go) will have an edge.

Asking a front-end developer to write a red-black tree is insane. Is anyone actually doing that?