Ask HN: How to prepare for a Front-end Developer interview? • Hacker News Board

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

#131

Post by hifumi » Mon, Aug 15, 2016, 2:45 PM UTC

enraged_camel wrote: post #74

pauljaworski wrote: post #63

Here are a few questions/problems I was asked in from-end interviews a couple months ago: Write a function that accepts an array of ints and a target number. If two of the numbers in the array can add up to the target, return their indices. (aka Two Sum) Write a function that accepts an int x and prints a spiral of "#"s so that the number of "arms" in the spiral equals x. Write a function that accepts a month and a y…

>>The good interviewers, IMO, gave me a "take-home" problem of building some mini front-end app that hit an API, and the really fun one involved reverse engineering an unpublished API - that's how I got my current job. I agree with you, but whenever this subject comes up, a lot of folks here on HN complain that they have full-time jobs and families and don't have time for "take-home" questions.

It sound like those people don't want to devote the time to get a new job. And thus don't really want the job.

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

#132

Post by franciscop » Mon, Aug 15, 2016, 2:50 PM UTC

bzalasky wrote: post #127

franciscop wrote: post #114

Earlier quoted context omitted.

I might have experience but that still looks totally trivial for me... is many people not passing the first test?

It's not meant to be difficult. You'd be surprised how many people don't pass this. The most important part of the interview for me is when we advance to talking about what a candidate has actually done.

That's my point, I've read many times that I'd be surprised how many times people don't pass this (and I agree) but I'd love to know how many. Could you share please?

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

#133

Post by pluma » Mon, Aug 15, 2016, 3:03 PM UTC

ricardobeat wrote: post #123

pluma wrote: post #109

Earlier quoted context omitted.

Try writing the same thing without a computer why don't ya. As an interviewer I can see why you would want to force someone to jump through arbitrary hoops like that but if someone can show me `() => i` and explain why that works, that would be good enough for me.

No need for the snark. There is still way more ES5 code being written than ES6. The point is demonstrating knowledge of closures and variable lifecycle, the how is irrelevant. I replied specifically because he said "I don't see the problem" - if you start with ES6 I can imagine it doesn't look like a problem at all.

If you can explain why that ES6 code doesn't share the problem, that's as good at demonstrating the knowledge you're looking for as restricting the candidate to an older subset of the language. I would accept "okay, now explain what distinguishes arrow functions from regular functions" as a follow-up question, but "now do it in ES5" seems arbitrary.

In fact I would argue it's important that if the candidate shows practical knowledge of ES6 you need to make sure they also grasp the actual semantics (i.e. they won't rely on implementation details of Babel and run into errors in native ES6 environments).

That said, if you are hiring for a dedicated frontend developer role, the majority of JS you write will have a build step. If it has a build step, you should use modern tooling. If you use modern tooling, you might as well include Babel to make the developers' lives less of a pain.

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

#134

Post by iLoch » Mon, Aug 15, 2016, 6:17 PM UTC

qaq wrote: post #48

iLoch wrote: post #29

Earlier quoted context omitted.

This is why SV needs to stop abusing the term "engineer" - because this is indeed work that can be done on the front end, but under no circumstances should you expect front end developers to know how to do this. If you have a specific need, or you're building something very complex, then you probably want an engineer -- most companies (including any of the big ones) typically only need developers. It's good to have e…

Right or you could have a "developer" tinker with stuff and that's how wind up with things like redux

Oh yeah absolutely - not trying to take anything away from developers particularly. Different skill sets, but practically the same outcome most of the time. That's a great example of why knowing how to create a BST from scratch isn't the only knowledge needed to build great software.

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

#135

Post by stevenwiles » Mon, Aug 15, 2016, 7:14 PM UTC

andrewstuart wrote: post #53

Most modern production quality software systems there days are implementing fibonacci algorithms as part of their core business rules, controlled via a red/black tree. Usually it's held together by a fizzbuzz architecture so as a minimum you should be able to whiteboard fizzbuzz. You should understand all these things well, and really if you are doing modern software development these things hould be day to day tasks…

All of this advice is especially relevant to a Front End Developer role. You'll want to go into this thing having a solid grasp of Big-O notation runtime efficiency of your favorite UI algorithms.

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

#136

Post by joeld42 » Mon, Aug 15, 2016, 7:29 PM UTC

When I interview front-end developers, I take a wireframe mockup, or sometimes just a screenshot (either from a real product, or just make one up), and ask "how would you implement this". I want to see if they know the toolkit, can make good choices, can discuss tradeoff (e.g. should something be a custom widget or a stock system), can discuss performance (what if that table had 100k items? would it still work?). Then I ask if they have suggestions to change or improve the design, just to see if they think of themselves as more of an implementer or as sharing the responsibility with the interaction designer (both have their place). Finally, I do make sure they can do simple coding tasks, and give them some questions to test their comp-sci background, though that wouldn't disqualify someone, it can help.

Oh yeah, I also ask them to talk about how to make an interface feel responsive even though most actions can trigger a network call that may take several seconds to respond.

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

#137

Post by bzalasky » Mon, Aug 15, 2016, 10:08 PM UTC

franciscop wrote: post #132

bzalasky wrote: post #127

Earlier quoted context omitted.

It's not meant to be difficult. You'd be surprised how many people don't pass this. The most important part of the interview for me is when we advance to talking about what a candidate has actually done.

That's my point, I've read many times that I'd be surprised how many times people don't pass this (and I agree) but I'd love to know how many. Could you share please?

Generally the candidates that don't pass that first question don't have sufficient experience with JavaScript. Sometimes this is because they have more experience on the backend and for whatever reason said they knew JavaScript on their resume and found themselves in the frontend portion of a fullstack interview. Other times the candidate has a lot of experience with CSS and layouts, but doesn't have much experience with JavaScript beyond jQuery. Out of five candidates, two might fail this... but it comes down to the candidates in the pipeline. Working closely with your recruiters can take that number down to zero. I've found that filters like this become more necessary when there are a lot of positions to fill.

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

#138

Post by russelluresti » Mon, Aug 15, 2016, 11:21 PM UTC

andy_ppp wrote: post #98

Closures, specificity, home made getElementsBySelector, DOM traversal stuff, weird IE things, coding standards, an understanding of how jquery works, how to protect against npm poisoning/leftpad issues, lodash, semantic naming strategies, being opinionated (why is BEM shit/great?), box model, floats, flex box, centering techniques, an understanding of how plane old js works, cross origin/same origin stuff, basic desi…

A couple of years ago, I would have answered the same way. Now, at least in the SF Valley area, these types of things are largely ignored and instead we're asking a lot more CS questions (algorithms, data structures, design patterns, etc). In fact, I'd say about 99% of interviews for a front-end position don't ask ANY CSS questions at all - they're all JS-based.

For example, in a recent string of interviewing here for a couple of large SF-based companies and startups, I've encountered questions like re-implementing jQuery, doing the JS for the game Snake, palindrome checkers, longest chain of ascending numbers in an array, shortest path, matching node (given a node in one tree, find the same node in an identical tree), and basically a whole bunch of other questions where only JS skill were assessed.

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

#139

Post by andy_ppp » Tue, Aug 16, 2016, 9:05 AM UTC

russelluresti wrote: post #138

andy_ppp wrote: post #98

Closures, specificity, home made getElementsBySelector, DOM traversal stuff, weird IE things, coding standards, an understanding of how jquery works, how to protect against npm poisoning/leftpad issues, lodash, semantic naming strategies, being opinionated (why is BEM shit/great?), box model, floats, flex box, centering techniques, an understanding of how plane old js works, cross origin/same origin stuff, basic desi…

A couple of years ago, I would have answered the same way. Now, at least in the SF Valley area, these types of things are largely ignored and instead we're asking a lot more CS questions (algorithms, data structures, design patterns, etc). In fact, I'd say about 99% of interviews for a front-end position don't ask ANY CSS questions at all - they're all JS-based. For example, in a recent string of interviewing here fo…

If people want to ask computer science question that's great but I'm not going to learn how to balance a binary tree (again) I'm going to get them to teach it to me in the interview by asking the right questions. If they can't see that I'm smart enough to pick new things up quickly I'll probably be trapped doing the same thing for them forever so I'd rather not work there :^)

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

#140

Post by jimcsharp » Tue, Aug 16, 2016, 11:03 AM UTC

hifumi wrote: post #129

cmenge wrote: post #120

Earlier quoted context omitted.

I agree that it's far from what is needed in everyday tasks, but in defense of that process: if you are unable to implement fizzbuzz, Fibonacci numbers, etc., I am almost sure you can't understand react sagas or dependency injection properly. Mixed with more open-ended questions (why was React built? how does it compare to Angular? What's a generator function?), I believe this isn't the worst type of interview. See t…

> their portfolios appear to be mostly borrowed plumes. I don't understand this phrase. What do you mean by borrowed plumes?

When you aren't being forthright with the position you held on a development team. If you were a late onboard to a project and spent your time firefighting bug reports, you could perhaps lend cachet to your resume by omitting the relatively minor role you had in the project. Then you'd be borrowing the "plume in your cap" from your team, who deserves more of the credit.

edit: this is my best-fit guess. I have no idea what I'm talking about.