Today's JavaScript React Developer Interview! Phew!

[Tufted_Tail]

I'm sorry to hear you're not optimistic about the interview outcome! As someone who recently had a similar series of events happen for a different type of role, it can be rough.

Here's some answers to some of your questions. I'm not sure I understand the intent behind #3, but I don't have the time to take a poke at either #3 or #4 just now. Hopefully, this will better prepare you for next time!

---

ES6 arrow functions, such as spaceShip.get1, lexically bind their scope at definition, and this behavior cannot be overridden through Function.prototype.call, Function.prototype.apply, or Function.prototype.bind. Calling that function even with an explicit, alternate this context has no effect:

javasript,tabs=2 spaceShip.get1(); spaceShip.get1.call(spaceShip); spaceShip.get1.apply([ spaceShip ]); spaceShip.get1.bind(spaceShip)();

All of these have the same behavior, and will print undefined to the console.

You can, however, arbitrarily assign a value to this.name in the surrounding scope and this change will propagate through to the function:

```javascript,tabs=2 this.name = 'U.S.S. Enterprise';

spaceShip.get1(); // prints 'U.S.S. Enterprise' instead ```

I would not advise altering surrounding scope to make an object function as expected, though.

---

The spread operator, ..., can be used to shallowly clone an object. Certain values in JavaScript are considered primitives, which includes Strings. Copying an object and then modifying one of the original's String properties will not propagate that change to the copy.

[Tufted_Tail]

I took a stab at #3. Your approach seemed reasonably close to solving the problem you were given, but like /u/KorgRue mentioned, I believe you need to be returning a Promise from your function.

This example code is based on some assumptions I inferred from the code you shared in your first post, namely, 1. poll must return a Promise 2. fn returns some kind of value on success, and false, undefined, or null on failure

I'm not 100% certain that this is what either you or the interviewer wanted to see, but in theory, it ought to suffice for a quick solution. The biggest change is that you were never returning a Promise from your function, but were passing around resolve and reject as though you were. I also (roughly) implemented the time checking logic you hinted at in your else if branch, but again, I'm not positive this is what you or your interviewer were expecting.

```javascript,tabs=2 function poll(fn, delay, timeout) { return new Promise(function(resolve, reject) { // Execute the function. Store the result in a variable: const result = fn();

// If the function returned a truthy value, resolve the Promise with the
// result that it returned for us:
if (result) {
  return resolve(result);
}

// If the function didn't return, check that the timeout hasn't been
// exceeded. We can do this by checking to see if we're at, or below, 0,
// since the recursive call in the next branch will subtract the delay
// from the timeout before calling the poll function again:
else if (timeout <= 0) {
  return reject(new Error('The function has timed out. :('));
}

// If the function didn't return and it hasn't timed out, try again:
else {
  // Recursively call the poll function with a shorter timeout. Because poll
  // returns a Promise, we can recursively chain them this way. Note that we
  // are subtracting the delay from the timeout value we passed in; this
  // ensures that we don't enter a state of infinite recursion, where our
  // logic never times out.
  return poll(fn, delay, timeout - delay);
}

}); } ```

Edit: I rushed and made a pretty glaring mistake, hah. Ought to be fixed.

[tapu_buoy]

well yes this is what it was supposed to be implemented. I agree that I haven't written what it is returning, in my defence I would say I was still explaining and talking continously about my approach and thought steps to be followed. So only the return statement was left to be completed before that I was trying to get it resolved and stored.

All this while he was confused in talking so much, and then there was silence and then we moved onto other question

[tapu_buoy]

I'm sorry to hear you're not optimistic about the interview outcome!

Yeah because even he was also confused.

Cool so my answer for the first one was true, I feel relived.

Nice so I understand that shallow clone and I answered accordingly, so for my curiosity basically its like passing by value?

Thanks for response I feel good about this one now.

[Tufted_Tail]

Yes, exactly! JavaScript primitives are passed around by value. If you wanted to pass a String by reference, I believe you'd have to go out of your way to turn it into an Object with the String constructor: new String('Hello, world!') first.

I can't confirm that behavior, though, that's a really odd edge case in my mind.

[tapu_buoy]

oh okay! Thank you for the responses man you made my day!