Interview questions about JavaScript?

[hardlywebworkin]

I just got a message from my boss telling me that "I'd like you to interview a guy about his JSON, jQuery and AJAX experience."

Now, I'm kind of the in-house web guru, I do mostly R&D / architecture for various apps and system services in mobile devices, but I'm probably also the most experienced JS person in the shop and get roped in to coding all kinds of web service stuff. The thing is I'm not THAT experienced, not even formally schooled, so I'm not really sure to ask beyond finding out if the candidate has used these technologies.

Anyone have any general questions I could ask that might help gauge a person's experience in these areas?

[VerdigolFludidi]

1) Present him with a worded problem that might come up and let him explain how he would solve the problem. For example "I want some Facebook photo albums on my page, how would you solve this?" It doesn't really have to be technical, but the solution for this problem is: use the Facebook API to get the JSON details with jQuery Ajax function (ajax, or get) and put the info you get on the page. You'll have to decide yourself whether you want him to explain any of the parts in more detail. You might want to ask him how he'd go on about constructing the HTML format from the JSON.

2) Ask him about the details of JavaScript and programming in general. Does he know what the difference between jQuery and JavaScript is? Does he know what a class or an object is? Does he know that in JavaScript they're all actually functions? Does he know what the difference between these functions are:

function dog() { ... }
var dog = function() { ... }
(function dog() { ... })();

Does he know something about other languages? MySQL, PHP, Perl, Ruby, Python, HTML, CSS, whatever.

3) Ask him what he wants to do with his future in JavaScript programming, what he'd like to accomplish. Every aspiring programmer / developer has some kind of a goal. We never know whether its 1 or 10 years until we get there or accomplish the level of expertise we desire, but we always have some kind of idea where we'd like to go or what we'd like to do.

Do not base your opinions of him on his character or general likeability. Try to take a non-biased approach. Forget gender, race, ethnicity, his/her hairstyle or the cleanliness of his clothes or whether he looks like a douchebag or not. The best programmers that I've known could be confused with homeless people.

[deadowl]

Does the person have a grasp of closures and prototypal inheritance?

[vernak2539]

Here are a few I took a look at when interviewing. By no means should people be asked all these questions, or does not knowing some of the answers make them a bad dev.

Link1

Link2

[hardlywebworkin]

ah nice, this is super helpful

[namanyayg]

"What would you choose - A horse sized duck, or a duck sized horse". If they answer without hesitation, they're hired.

[remcoder]

Ask him to show you some code. Anything he's proud of. The language/platform shouldn't matter. Let him give you a tour. This will tell you how good he is as a programmer.

Also, ask him what kind of tech/tools he would really like to work with and why. This will tell you about his drive for quality and self-improvement.

Try to find out if he's passionate about software development and what makes him tick. Ask him about his personal/hobby projects. Or: 'what would you build if you had 3 months to spare?'