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JavaScript

Posted by Joe Williams
Joe Williams
4,014 Points

Why do I keep getting the error, "TypeError: xxx is not a function?" Is there a better way to do this?

I am trying to test myself a bit by combining some of the things I've learned in these beginning Javascript courses. What I'm trying to do is make it so when you arrive to a website, you're greeted with an alert, asked your name, and if it is Joe, I want it to print to the console, "the user's name is joe." Otherwise, I want it to print, "the user's name isn't joe."

What am I doing wrong?

alert("Welcome to my first mini-program.")
firstPrompt = prompt("What is your name?")

(function () {
    if (firstPrompt == 'joe') {
        console.log("The user's name is joe")
    } else {console.log("The user's name isn't joe")}
})()

My logic was that I needed the function to run automatically when the user arrives to the page, and I remembered learning that a benefit to the anonymous function is that you can immediately call it.

Am I close, or is this attempt way off? This is assuming that the user types in "joe" in lowercase, and no other name, when prompted after loading the page.

((( Also, for the record, inside the function I also tried it as (firstPrompt ==='ally') )))

Alex Lewis
Alex Lewis
15,619 Points

You just needed to add some semicolons to your statements. Javascript was getting confused since you were missing a few.

Here's what you should have:

alert("Welcome to my first mini-program.");
firstPrompt = prompt("What is your name?");

(function () {
    if (firstPrompt === 'joe') {
        console.log("The user's name is joe");
    } else {
        console.log("The user's name isn't joe");
    }
})();

Check out the jsfiddle

1 Answer

Chris Shaw
Chris Shaw
26,676 Points

Hi Joe,

The anonymous function isn't needed as it offers no benefit to this example since your declarations all occur within the global scope of the page, normally you only need to use anonymous functions when you want your code locally scoped so it can't be accessed by anything not in that same scope.

In any case the below would suffice and achieve the result you're looking for, of course semi-colons aren't a requirement but it's better to have them to avoid any issues down the track.

alert("Welcome to my first mini-program.");
firstPrompt = prompt("What is your name?");

if (firstPrompt === 'joe') {
    console.log("The user's name is joe");
} else {
    console.log("The user's name isn't joe");
}
Joe Williams
Joe Williams
4,014 Points

Thank you for the feedback! That makes a lot more sense. In my head, the function was necessary for the program to run. Now I realize that "if/else" will run automatically simply by meeting the correct criteria.