Some minor comments:

• Q2: "Local scope can be local to a function or a block." Or module - another local scope

• Q2: "Variables defined using var have function scope."/"Variables and constants defined using let and const have block scope." Unless used in the global scope, at which point they're global

• Q2: "In case of a block scoped variable, its value is inaccessible before its first assignment." More accurately, its before the location of the declaration. You can declare a variable with let without defining it and still be able to access it prior to its first assignment.

    let x;
    console.log(x); // Ok, = undefined 
    x = 1; // first assignment
  

• Q3: "JavaScript functions have prototypes." Not all functions. Arrow functions and methods do not.

    () => {} // no prototype
    { foo(){} } // foo: no prototype
    class { foo(){} } // foo: no prototype
  

• Q5 (and Q4): No use of super.deposit()?

• Q6: "In JavaScript, this is a function scoped variable." It also exists in global.

• Q6: "Under normal circumstances, this refers to the object owning the function." Specifically, the function call, not the function itself. this, under those normal circumstances, is determined dynamically at call time and applies to the call itself rather than the function object.

• Q6: "In global functions, this equals the global scope." Only if its being called from the global object, otherwise its undefined (given that it was mentioned earlier, "this test is in strict mode").

• Q8: "When using the global symbol registry, we get the exact same symbol belonging to the string 'a', whenever we call Symbol.for( 'a' )." This feels a little out of place without first mentioning how symbols are inherently unique.

• Q9: "A correct check [to see if a value is an Array] is the usage of the instanceof operator:" This is a way to check, but its less correct than the best solution of Array.isArray... though still more correct than comparing the constructor. Actually the typeof checks below might be better since it works across multiple globals. Without isArray, its often suggested instead to use Object.prototype.toString and compare to "[object Array]" since it would work in most cases, though even this approach can be interfered with using toStringTag. At any rate, I think the usage of "correct" should fall to isArray and not instanceof.

Senior role interview probably vary a lot more than a typical mid-level interview, since from my experience there's a different meaning to 'Senior' everywhere. Some places it's more of a managerial role, others its more of a technical knowledge role. Nevertheless last time I interview it was for a place that also uses primarily React and Node. Here's a general gist of what I was asked for a mid-level Front-end interview with some Node added since I would be expected to write some of that as well:

• A lot of basic to intermediate js questions. Things like context/this in Javascript. Prototype knowledge, inheritance model, asynchronous behavior (callbacks, promises, async/await, a little bit of generators but only because I mentioned it), the event loop/callback queue

• React specific questions revolved around patterns like Higher order Components, Render Props/Function as child, why use React in the first place? Comparison to past popular frameworks as well as current ones (since I was coming from a place that used Vue), JSX vs templates, asking about past projects, etc.

• Node questions revolved around more of the event loop, general http questions, a little graphQL (i had never used it but heard of it), some specific framework knowledge around express/koa (they don't use express).

I was interviewing for more of a Front-end focused role, but expected some Node stuff anyway. Not as much around Node was asked, but a lot around general JS stuff. So the interview also consisted of a lot of knowledge around CSS, general layout best practices (semantic html), performance in the browser, etc.

I am not a fan of questions that ask CS fundamentals. I have never had to implement BinarySearchTree as part of my job. It has no value and doesn't indicate anything about the candidate being able to perform his/her job except remembering what they did in college

The best question on this is:

My website is slow. Walk me through diagnosing and fixing it. What are some performance optimizations people use, and when should they be used?

Otherwise not sure the value of memorizing how to implement quickSort or MergeSort will help you be a valued front-end member of the team.

What I would prefer to see as questions asked:

• Can you explain how eventing works in node / JS?

• Can you build an event emitter?

• Can you explain the difference between declarative programming vs. imperative programming? Can you give an example?

• I have an error in this code sample.. can you go through and fix the problem? How would you approach fixing the problem? What tools would you use?

• How would you refactor this code piece? What are some code smells? What would you do about testing?

• If you are hitting an API and all of a sudden you get an error. What do you do? What if the errorcode is a 500? 404? 429?

• JavaScript has class syntax from es6 onward. Why would you use it? What is JS compiler actually doing when you write a class syntax? What is prototypical inheritance? What write methods on the prototype?

• CSS questions? Flexbox? Grid? Box Model? BEM?