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- Now this is gonna be
another really quick video

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where I talk about how you can deal with

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optional parameters in a function.

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Let's say I have a function

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that's gonna be print name and age.

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It's gonna take in a name and an age.

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So this age is a number

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and the name here is going to be a string.

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And we'll just define this
function really quickly

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as a simple console log of name and age.

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Here we go.

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What I can do is I can
call print name and age

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and I can pass it in a name
and I can pass it in an age.

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That works just fine.

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But what happens if I want this
age property to be optional?

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'Cause in JavaScript, we
know there's often times

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where you want to create a function

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where sometimes you pass it one parameter,

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sometimes you pass a two,

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sometimes you pass a three and so on.

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And in our case, I want
this age to be optional.

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This is really common

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if you have like an options argument.

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For example, we have some options

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and they're set to an object

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with some different types inside of it.

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That's a very common thing

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that you would want to be
optional inside a JavaScript,

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because by default you just
use the default values,

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otherwise it's going to fall back

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to actually using whatever
values you pass to it.

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What we can do is we can
actually emulate that

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by instead here just having our options.

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And let's just say our options
is going to be debug mode

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and this is going to be a
boolean, just like that.

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So there's our option types.

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What we can do is we can
pass in here an object

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that would have debug mode of true.

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We can pass this in if we want,

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but if we leave it off it's
going to give us an error,

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which is probably not
something that we want.

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So in our case, to make this optional

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all we have to do is just
put a question mark after it.

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And that's just telling TypeScript,

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hey, this is now an optional property.

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Now what we can do inside of here

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is we can pass it along if
we want, as you can see here,

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and it's going to work fine.

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Otherwise we can leave it off,

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and again, it's going to work just fine.