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JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops Create a `do...while` loop

Posted by Katherine Lucas
Katherine Lucas
658 Points

What am I missing?

It says I have a parse error. Need help please.

script.js 
var secret;
var correctGuess = false;

do {
  secret = prompt('What is the secret password?");
  if (secret === 'sesame') {
    correctGuess = true;
  }
  while ( ! correctGuess ) {   
}
document.write("You know the secret password. Welcome.");
index.html 
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript Loops</title>
</head>
<body>
<script src="script.js"></script>
</body>
</html>

2 Answers

miikis
miikis
44,957 Points

Hi Katherine,

You're missing a couple things: your do...while syntax is messed up and your prompt question's quotations don't match. Fix those and it runs fine; let me know if it doesn't.

Dan Weru
Dan Weru
47,649 Points
Dan Weru
Dan Weru
47,649 Points

Hi Katherine, you're doing great just make a few tweaks.

var secret;
var correctGuess;

do {
  secret = prompt("What is the secret password?");
  if (secret === "sesame") {
    correctGuess = true;
  }
}while (!correctGuess);
document.write("You know the secret password. Welcome.");

This should work ... be consistent while using double(") or single(') quotation marks.

You must not necessarily set a value(initialise) for the correctGuess variable ... just declaring it with no set value defaults to undefined. You could set it to false though; it does no harm.

miikis
miikis
44,957 Points

Your refactor is wrong — it doesn't make any sense. The goal of refactoring is to optimize for something; what exactly are you optimizing for here?

miikis
miikis
44,957 Points

Also, null is not strictly equal to false.

Dan Weru
Dan Weru
47,649 Points
Dan Weru
Dan Weru
47,649 Points

Her code was not working in the first place. The document.write function was outside the body of the loop. That means it would be called every time, regardless of the loop. That's why i moved it into loop's body. I'm also aware that null and false are not strictly equivalent. However, in respect to the scope of this exercise, that is besides the point.

miikis
miikis
44,957 Points

"That means it would be called every time, regardless of the loop."

No, it wouldn't. The loop only exits once secret equals "sesame." If secret doesn't equal "sesame," the loop runs forever — document.write would just never be called. I'm not saying that your way won't work, just that it's completely unnecessary... and a slippery slope, at that; why not wrap it all in separate functions and implement separation of concerns while you're at it? Katherine's problem was syntax ... and that's it. I didn't re-write the code for her because I thought she might find figuring it out the syntax herself to be more educational.

As a side note, you were wrong about correctGuess being null as well — it'd be undefined.

Dan Weru
Dan Weru
47,649 Points
Dan Weru
Dan Weru
47,649 Points

I ran it in the browser ... it runs both ways. You're right ... you're obviously seasoned in javascript than I'm. Pleasure.