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Over the last lectures,

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I spent a lot of time on functions

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because functions are a super crucial and key feature

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which you will need all the time in JavaScript development

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and that's why you need to understand them.

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And I hope I could explain those key basics.

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We are going to write and use a lot of functions

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throughout this course so you will get a lot of practice,

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but the general idea should be clear by now.

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I wanna emphasize again that functions don't need to return

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and don't need to take parameters.

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It will depend on which kind of function you're writing

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and what it's doing.

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I also wanna emphasize again that functions of course

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can execute multiple steps in there

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and you can of course also introduce variables in there,

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like result, which then are only available in this function.

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And then here we could store userAge minus 18 and result

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and return the value stored and the result here.

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That would be an alternative way of writing this function,

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arguably an unnecessarily complex way,

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but to understand that you can do

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all these things and functions,

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I want to switch to that code for now.

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So which code goes into a function?

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And whether you return and/or whether you use parameters

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depends on what your function does.

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As I said, we're going to write many functions

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throughout this course,

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and therefore there will be plenty of opportunities

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to practice this.

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This is the general feature of functions.

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That's how it generally works.

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And now let's build up on that.