32 lines
1.0 KiB
Markdown
32 lines
1.0 KiB
Markdown
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# function
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A function with inputs and outputs. #docs #function #language
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### @parent js/language
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To add a **functions** to your script, click the `script` button, then click the `+` `add new function` button
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### functions
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A **function** takes [inputs](/microbit/actionparameters), runs code and (optionally) returns an output.
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TouchDevelop functions are similar to `mathematical functions`. Consider the function that computes the square of `x`: `square(x) = x*x`. In code, it would look like this:
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```
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export function square(x: number) : number {
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let result: number
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return x * x
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return result
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}
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```
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### private function
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An function can be marked as **private** in the properties. A private function is not visible outside a library (if the script is a library)
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### documentation
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The comment(s) at the beginning of a function used to provide a description of its purpose. This text will show in the help area when the function is called from the code editor. This is particularly useful for [libraries](/microbit/libraries).
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