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Interview questions for senior roles won't (or at least shouldn't) be about language specifics but instead about managing a team, distributing technical work, managing timelines etc. Needless to say, depending on the company, ymmv.
Why creating an element and afterwards setting it to invisible, will never end with a 'blinking' element.
I agree with others though that you probably won't get the trivia treatment, I wouldn't give one and I don't see them being done by coworkers... But it doesn't hurt to be prepared. So long as you don't present yourself as a "Master" I would think the knives would be less likely to come out. Things like this github has https://github.com/denysdovhan/wtfjs are on the mean spectrum to use against some so-called master, the meanest might probably be demanding they do something with representations like in http://patriciopalladino.com/blog/2012/08/09/non-alphanumeri...
Explain why ['1','1','1'].map(parseInt) returns [1, NaN, 1] but ['1','1','1'].map(n => parseInt(n)) returns [1, 1, 1].
['1', '2', '3'].map(parseInt)
Why creating an element and afterwards setting it to invisible, will never end with a 'blinking' element.
If I'm ever in a position where I'm responsible for technical interviews I'm pretty sure I'll give them open internet questions. Then ask them to talk me through their thought process. Even though questions could probably be answered by anyone with decent skills, the best will certainly stand out in how they talk you through their thought process.
Explain why ['1','1','1'].map(parseInt) returns [1, NaN, 1] but ['1','1','1'].map(n => parseInt(n)) returns [1, 1, 1].
What the hell, who on earth thought that behaviour would be a good idea?
[1, 2, 3, 4].reduce((x, y) => Math.min(x, y))
[1, 2, 3, 4].reduce(Math.min)
But as other have already pointed out, quiz-type questions that are trivially searchable and irrelevant for practical programming tell about a culture of the company. Use that as hint if you want to work for them.
You might see a dumb question that is just a bunch of spaghetti nonsense you'll have to unravel. Explain what this ridiculous codeblock does.
Definitely expect to see closure-based problems. You can almost bet your money on seeing an anonymous function in a loop printing an unexpected value of i:
(copy these code blocks into your browser console and test them out)
for(var i = 0; i setTimeout(func, 0);
variable scoping with var, let and const. Variable and function hoisting. Expect brain teasers exploiting the differences in const / let and var:
const x = [1, 2, 3];
for (var i = 0; i Earlier quoted context omitted.
What the hell, who on earth thought that behaviour would be a good idea?
.map(fn) calls its callback with three arguments, the value, the index, and the full array. Then parseInt takes two arguments, the string and the base (radix). "1" of base 0 is 1 "1" of base 1 is NaN "1" of base 2 is 1 The gotcha here is if you map(fn), you're going to get all three arguments sent to the fn, where map(v => fn(v)) explicitly only sends the first one.