pxt-calliope/docs/js/call.md

Call a function

The simplest way to get started in JavaScript with your micro:bit is to call one of the micro:bit's built-in JavaScript functions. Just like Blocks are organized into categories/drawers, the micro:bit functions are organized by namespaces. The basic namespace contains a number of very helpful functions:

basic.showString("Hello!")

If you want to see all functions available in a namespace, simply type basic followed by .; a list of all the functions will appear.

We call this feature "Intellisense". Continue typing to select one of the functions, or click on one of the functions to select. You also narrow down the set of functions by typing, as below:

Function parameter values

You might have noticed that the call showString above takes one parameter value, the string to be scrolled on the LED screen. There is a second (optional) parameter that controls the speed of the scroll. Try this:

basic.showString("Hello!",50)

Intellisense shows all the available parameters for a function.

Left and right parentheses, please!

Whenever you want to call a function, you give the name of the function followed by ( and ending with ). Inbetween the left and right parentheses go the function arguments. If a function has zero arguments, you still need the parentheses in order to call the function. For example

basic.clearScreen()

It's a syntax error to have a left parenthesis without the "closing" right parenthesis:

basic.clearScreen(

~button /js/sequence

NEXT: Sequencing Commands

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