Ruslan's Tech Blog

How to interview [memo]

Wed, 12 Jun 2019 00:00:00 +0000

Just met this nice article by Laurie Voss called You suck at technical interviews.

Here is TL;DR from there:

many interview techniques test skills that are at best irrelevant to real working life
you want somebody who knows enough to do the job right now
or somebody smart and motivated enough that they can learn the job quickly
you want somebody who keeps getting better at what they do
your interview should be a collaborative conversation, not a combative interrogation
you also want somebody who you will enjoy working with
it’s important to separate “enjoy working with” from “enjoy hanging out with”
don’t hire assholes, no matter how good they are
if your team isn’t diverse, your team is worse than it needed to be
accept that hiring takes a really long time and is really, really hard

Here is the link to original post

Good read.

Frontend Developer interview. Help for interviewers (1)

Mon, 16 Jul 2018 00:00:00 +0000

The problem

I’m not a huge fan of questions on interviews similar to:

do you know X
did you use Y
what is the difference between X and Y
etc…

Live coding is not something I like as well due to some reasons.

What really helps me to understand how good candidate is, is to discuss some real situations with him/her.

Below is one hypothetical projects to discuss with a candidate.

Also check out the Part 2 of this post

The project

Given a Single Page Application (SPA). The main purpose of the app is to store movies a user added for himself. Some kind of bookmarks.

Features are:

add new movie
- add title
- add description
show list of movies a user have added (only his/her movies)
API has all required routes to store/fetch movies of a user

The problem is our users have no stable internet connection for some reason.

The question how we can allow users to save movies even if the internet connection is lost?

Possible flow:

Candidate usually starts with the idea to use Local Storage for storing all the data while internet is off. Which is definitely make sense. Here you can ask how he/she is going to integrate it:
- Should it be separated module/class? (definitely yes)
- Should developer use that module/class when internet is off and use calls to a server when internet is on? (the answer can be very varied, but it should be some kind of general class that internally detects internet activity so the user of module (developer) should not think about current state of internet connection and use different modules/classes for saving/fetching movies)
- Probably there should be some kind of queue to make sure movies are sent to remote API in the same order they were added.
When (if) you have discussed with a candidate all that above’s points and he/she did great you can complicate the task a bit and say “Now we want to extend our add new movie page with an image of movie”.
- Here you should pay attention to the way a candidate thinks. He/She probably should come up with the idea that using Local Storage will not be enough if we’re going to store images. Remember that we cannot use links since we’re possibly offline.
- Basically there are not too many possible options. IndexedDB is something we can try to use in this case.

Don’t hesitate to ask other questions you’re interesting in. It’s also OK if candidate don’t know the answer, sometimes we don’t have answers too. We usually google in this case, but a candidate can’t so it’s completely OK to give some help to him or her.

If you’d like to get more understanding on what knowledge the frontend candidate should have please refer to How to Hire a Front-end Developer by TopTal.

Take a look at another project you can discuss with an applicant here.

Frontend Developer interview. Help for interviewers (2)

Mon, 16 Jul 2018 00:00:00 +0000

If you didn’t look at Part 1 of this post please check it out.

Project 2

Given a news site and its admin area. In admin area there are many users. Each user can edit a news-post.

Our goal is to make sure only one user can edit a post even if multiple users are visited the same news-post for editing. Users visited a news-post after the first user should see the “someone else is editing the post” message.

More info about the project:

It’s not a single page application
Backend part of the code already able to lock/unlock the post internally (we just need to call the function).
Backend developer can implement endpoints/services a candidate ask.

Possible flow:

Candidate usually come up with the idea to use Web Sockets. If so, you can ask candidate about how it should work.
- What message(s) should be send by web socket client to a server?
- What answer should be send by web socket server so client can know that post is blocked?
- How to make sure two users will not block the post?
- When user leaves a post who should be the next “owner” of a post if multiple other users are on a post page?
When you have discussed all that possible implementations for web socket you can tell candidate that “unfortunately we don’t have ability to setup web socket server on our production and have to come up with something else”.
Something else is long polling technique which is basically periodic Ajax requests to a server.
- Frontend can have two Ajax requests sending by interval (one is to lock, another one is to check if locked)
- Backend should receive the “lock” and lock the post TEMPORARY.
- If no another “lock” request received by the same user we should unlock the post (temp record should be removed)
- Lock the post when there is no “lock” on the post and mark that post is locked by a user.

I hope this project and the project from Part 1 will help you to understand more about your candidate.

Work remotely by Julia Evans

Mon, 19 Feb 2018 00:00:00 +0000

Really, really awesome blog post from Julia Evans about working remotely.

She has described every worry I have and explained how she managed work over them.

Just found out her blog and it seems very interesting in general.