Define types for ‘g’ and ‘WIDGETS’

typescript/types/main.d.ts

@@ -1,3 +1,5 @@
+/// <reference path="other.d.ts" />
+
 /**
  * Class containing [micro:bit's](https://www.espruino.com/MicroBit) utility functions.
  * @url http://www.espruino.com/Reference#Microbit

typescript/types/other.d.ts

@@ -0,0 +1,9 @@
+declare const g: typeof Graphics;
+
+type WidgetArea = "tl" | "tr" | "bl" | "br";
+type Widget = {
+  area: WidgetArea;
+  width: number;
+  draw: (this: { x: number; y: number }) => void;
+};
+declare const WIDGETS: { [key: string]: Widget };