A type refers to a class of data and the operations permitted on that class of data. The following built-in types are supported for the micro:bit:

Basic (primitive) types

  • Number: an integer number (32-bit signed)
  • String: a sequence of characters
  • Boolean: true or false

Complex types

  • Array: a list of items of a primitive type


  • Function: code you can reuse anywhere in a program


  • Buffer: temporary part of memory used to transfer data between your program and devices

User data

TypeScript allows you to create user-defined classes of data.

class Foo {
    public bar: number;
    baz() {