No they're not! Virtually no javascript developer needs to know about TCP.
Ajax doesn't go wrong. Most people abstract it even further using jquery and probably don't really know about how XMLHtttpRequest works.
What you've just said is absolute bullshit. Complete and utter horseshit. It's an artificial barrier you've erected to filter out people who aren't like you.
How wrong would you have had to write your javascript that you'd need to start knowing the specifics of two levels of abstraction down?
I am completely flabbergasted that a professional programmer would claim they needed a high level of understanding of TCP to write javascript.
I think you're misinterpreting the use of "high level" here. It's not that the candidate needs "a high level of understanding", it's that they need "a high level understanding". "High" here is in reference to the level of abstraction.
A high level understanding could mean something as simple as understanding the request-acknowledge nature of TCP, as opposed to the 'fire and forget' mechanism of UDP.
As to the claim that virtually no javascript developer needs to know TCP, that becomes less of a truth the closer you get to experimenting with tech like websockets, which is increasingly becoming part of javascript developers' jobs.
I think you're latching onto a narrative that you already made up about the poster before you even began this debate.
There's a large leap between what the poster is saying "I ask a wide range of questions to catch red flags if they get all wrong", and what you're saying "the poster is saying that javascript devs NEED to know TCP! Obviously an elitist filtering mechanism!".
Exactly this. A "pass" on that question consists of mentioning HTTP, DNS, and (perhaps with some prompting about what protocols underlie HTTP) TCP. A strong pass involves being able to tell me that DNS is usually UDP based, and being able to describe what distinguishes TCP from UDP. A very strong pass involves being able to describe in detail recursive DNS queries, talk about the fact that DNS can use TCP rather than UDP for queries or replies larger than what fit in a single packet, being able to tell me a bit about how TCP congestion control, sequence numbers, acks, Nagle's Algorithm, and the like work.
I should point out that I recently talked to a college junior who got a "very strong pass" on this question as a front-end intern candidate. If she can do that as a front-end oriented candidate with only a couple of years of experience in school, I don't think it's unreasonable to expect a professional with several years of experience to have at least the basic knowledge that TCP exists.
Some people are stronger in one area than another; so I cover a number of areas, and expect them to do well on a majority, but not all, of the questions. Even if you fail this question, just saying that you don't know anything about networking, if you do well at all of the others we will bring you in for the in-person interview; we have recently hired someone who simply said "I don't know" on this question, and was a bit fuzzy on the big-O questions, but did fine on on all of the rest.
Yes, this. Thank you for a reasonable reply to an unreasonable post.
(And as to the rest of his very angry post, I'm not a front-end developer, I do platform work and what some folks call devops. I can tell you exactly how XMLHttpRequest works, in detail, with diagrams. I can also go on at length about the DOM, the travishamockery of CSS, as much JavaScript minutiae as one would like...I think a basic understanding of the world around us is important to being good at things. Being "a front-end programmer" doesn't mean you should be so incurious as to not know how things you don't touch every day but directly inform the things that you do actually work.)
Except when it does. Did you miss the bug report I linked, in which it went wrong in one way when Firefox sent something as two separate packets, which caused IIS's HTTP implementation to break, and then when that was fixed the fix caused other regressions:
And this is only one of many such bugs; I've seen others in practice as well. It requires no special use of JavaScript to hit such bugs; just an unfortunate interaction between the particular browser and back-end server, of which there are many possible combinations, especially when you add transparent proxies into the mix.
By the way, when I'm looking for a frontend developer, I'm also not looking for someone to do the very most basic CRUD app plus some JavaScript for interactivity. I'm looking for someone to be able to do a rich, desktop-style app that pushes the boundaries of what can be done with HTML5 video. This is an area where you will be running into browser bugs on a regular basis, and need to know when to stop trying to solve the problem yourself and push the bug report upstream to the browser vendors, and in order to be able to do that it helps to have a knowledge of what is going on at that level. For this application, we accept that we will only be running on the very latest releases of a few select browsers, until interoperable support for the kind of stuff that we're working on becomes more widespread.
Ajax doesn't go wrong. Most people abstract it even further using jquery and probably don't really know about how XMLHtttpRequest works.
What you've just said is absolute bullshit. Complete and utter horseshit. It's an artificial barrier you've erected to filter out people who aren't like you.
How wrong would you have had to write your javascript that you'd need to start knowing the specifics of two levels of abstraction down?
I am completely flabbergasted that a professional programmer would claim they needed a high level of understanding of TCP to write javascript.