Where do I put return .toLowerCase(); in this program to make it exit even if I put EXIT

Question

I'm trying to make it so that I can exit this program with exit even if someone enters EXIT ExIt, EXit, etc. I tried putting it at the end of the var input at the beginning of the string and at the end of the string in the "}while" statement and it still not getting it to work. Does anyone know where I should put it?

<!DOCTYPE html>
<html>
<head>
<title>Project 1 – Michael Fiorello</title>
</head>
<body>
<h1>Robot Speak</h1>
<script>
    do{
    var input = prompt ("Please enter 1, 2, 3, or exit.");{
    if (input == "1")
         {
             alert ("THANKS!")
         }
    else if (input == "2")
        {
        alert ("COOL!")
        }
    else if (input == "3")
        {
        alert ("AWESOME!")  
        }
    else if (input == "exit")
        {
       alert ("Okay") 
        }
    else 
        {
        alert ("You need to enter something")
        console.warn("You need to enter something");
        }
        }
        }while(input != "exit")
</script>
</body>
</html>

Might want to watch the language. `var input = (prompt("...") || "").toLowerCase()` — nnnnnn, Feb 27 '17 at 00:47

Psi · Answer 1 · 2017-03-03T20:50:29.540

1

else if (input.toLowerCase() == "exit")
{
   alert ("Okay") 
}

As pointed out in the comments, if the user cancels the prompt, the result will be null. To catch this case, you should test for this value as well before coming to the line i wrote above:

if (input == null){
    handleCancel();
}
...
else if (input.toLowerCase() == "exit")
{
   alert ("Okay") 
}

In case you want "exit" and a press on cancel treated as program termination, you start testing for that case:

var goOn = true;

while(goOn){

    var input = prompt ("Please enter 1, 2, 3, or exit.");
    if (input == null || input == "exit")
    {
         goOn = false;
         // handle cancel
    }
    else if (input == "1")
         {
             alert ("THANKS!")
         }
    else if (input == "2")
         {
            alert ("COOL!")
         }
    else if (input == "3")
         {
             alert ("AWESOME!")  
         }
}

edited Mar 03 '17 at 20:50

answered Feb 27 '17 at 00:47

Psi

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This would give a TypeError if the user canceled the prompt. Also, there is another spot in the code that tests for `"exit"`. – nnnnnn Feb 27 '17 at 00:51
That's true, he just asked where to put the function call. I will update the answer anyway – Psi Feb 27 '17 at 00:52
Thanks for the help. Asking my professor if he wants the only way to exit to be by inputting it or not before I fix that part. – TheShadowGamer Mar 03 '17 at 01:35
Okay so my teacher wants cancel to also exit, so how would I go about it so it doesn't give the error when cancel is pressed? – TheShadowGamer Mar 03 '17 at 20:41
you just do nearly the same as above, i will edit my anwer – Psi Mar 03 '17 at 20:47
Thanks for the help – TheShadowGamer Mar 03 '17 at 21:01

score 0 · Answer 2 · edited Aug 07 '17 at 02:31

toLowerCase() may be invoked after null checking (i.e. when the prompt is cancelled) and when any case-insensitive comparisons are taking place.

To reduce the amount of comparisons, you may also use an infinite loop with a break upon hitting the required response.

You've also added an extra unneeded block, starting after prompt. This may be removed.

while (true) {
    var input = prompt("Please enter 1, 2, 3, or exit.");
    if (input == null){
        // Handle failure to specify a value
    } else if (input == "1") {
        alert("THANKS!");
    } else if (input == "2") {
        alert("COOL!");
    } else if (input == "3") {
        alert("AWESOME!");
    } else if (input.toLowerCase() == "exit") {
        alert("Okay");
        break;
    } else {
        alert("something else");
        console.warn("You need to enter something");
    }
}

This will have an error as well, if the user cancels the prompt. Additionally, it will always call toUpperCase which is an overhead when there are mostly numbers expected. No need to call it every time... — Psi, Feb 27 '17 at 00:56
Watch the profanity. Read the ["Be Nice"](http://stackoverflow.com/help/be-nice) policy. — elixenide, Aug 07 '17 at 02:31

Where do I put return .toLowerCase(); in this program to make it exit even if I put EXIT

2 Answers2