55 lines
1.7 KiB
Markdown
55 lines
1.7 KiB
Markdown
# Call a function
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The simplest way to get started in JavaScript with your micro:bit is to
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call one of the micro:bit's built-in JavaScript functions. Just like Blocks
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are organized into categories/drawers, the micro:bit functions are organized by
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namespaces. The `basic` namespace contains a number of very helpful
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functions:
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```typescript
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basic.showString("Hello!")
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```
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If you want to see all functions available in a namespace, simply type `basic`
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followed by `.`; a list of all the functions will appear.
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We call this feature "Intellisense". Continue typing to select one of the functions,
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or click on one of the functions to select. You also narrow down the set of functions by typing, as below:
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## Function parameter values
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You might have noticed that the call `showString` above takes one parameter value,
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the string to be scrolled on the LED screen. There is a second (optional)
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parameter that controls the speed of the scroll. Try this:
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```typescript
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basic.showString("Hello!",50)
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```
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Intellisense shows all the available parameters for a function.
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## Left and right parentheses, please!
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Whenever you want to call a function, you give the name of the function
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followed by `(` and ending with `)`. Inbetween the left and right
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parentheses go the function arguments. If a function has zero arguments, you still
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need the parentheses in order to call the function. For example
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```typescript
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basic.clearScreen()
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```
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It's a syntax error to have a left parenthesis without the "closing" right parenthesis:
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```typescript
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basic.clearScreen(
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```
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### ~button /js/sequence
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NEXT: Sequencing Commands
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### ~
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