TypeScript - Functions with default values for their arguments

If there's any risk of of not getting one ore more of the arguments defined in the function's signature, you can set default values for your function arguments. By doing this, you make the argument optional.

Notice that you can leave off the third and even the second argument.

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function SayHello(name: string, feeling: string = "good", hungry?: boolean): void
{
    console.log("**************************");
    console.log(`Hello ${name}`);
    if(feeling ==="good")
    {
        console.log("I'm glad you are feeling good.");
    }
    else
    {
        console.log("I hope you are feeling good.");
    }

    if(hungry !== undefined)
    {
        console.log(`Are you hungry? ${hungry}`);
    }
}

SayHello("Ricky Bobby", "so-so", true);
SayHello("Ricky Bobby", "so-so");
SayHello("Ricky Bobby");