# Default Parameters

Let's understand default parameters, shall we? 😁

We can craete a function that writes a greeting to the console:

function writeMessage(name) {
  console.log(`Hi, ${name}!`);
}

Let's call it with a name:

let name = "Daniel";
writeMessage(name);

And it prints out:

Hi, Daniel!

Cool 😄

But what happens if the name variable doesn't have a value?

let name;
writeMessage(name);

This prints:

Hi, undefined!

Well, this is not good 😦

Maybe we want to say: "Hi, there!" if there is no name.

We can do this with default parameters:

function writeMessage(name = 'there') {
  console.log(`Hi, ${name}!`);
}

Now, it prints:

Hi, there!

Also, we can call the function with no parameter and the default value is used again.

# OR operator

Prior to these, we would use the || OR operator:

function writeMessage(name) {
  name = name || 'there';
  console.log(`Hi, ${name}!`);
}

Now, the default paramters are more elegant and descriptive. 😄