Declaring and Calling a Function

Here's how you make a function:

function showBanner() {
  console.log("=====================");
  console.log("  Welcome, friend!  ");
  console.log("=====================");
}

Let's break it down:

• function is the keyword that says "I'm making a function."
• showBanner is the function's name. Same naming rules as variables (camelCase, no spaces).
• () the parentheses hold the function's inputs. This one has none, so they're empty.
• { } the curly braces contain the body: the code that runs when the function is used.

This is called declaring (or defining) a function. But here's the thing: if you run that code... nothing happens. Nothing is printed at all!

That's because declaring a function is like writing a recipe on a card. Writing the recipe doesn't cook anything. To actually make the dish, you have to follow the recipe. In programming, we call that calling the function (or "invoking" it, if you're feeling fancy). You call a function by writing its name followed by parentheses:

showBanner();

=====================
  Welcome, friend!  
=====================

And you can call it as many times as you like:

showBanner();
console.log("Some other stuff happens here...");
showBanner();

=====================
  Welcome, friend!  
=====================
Some other stuff happens here...
=====================
  Welcome, friend!  
=====================

Now if someone wants stars instead of equals signs, you change it in one place, and every banner updates.