refactor(helpers): modularize coinflip and outsideCoordinates

src/helpers/chance.ts

@@ -0,0 +1,6 @@
+/**
+ * Returns true or false.
+ */
+export function coinflip() {
+  return Boolean(randi(2))
+}

src/helpers/coordinates.ts

@@ -0,0 +1,14 @@
+import { coinflip } from './chance'
+
+/**
+ * Generate random coordinates outside the camera view.
+ */
+export function outsideCoordinates(x: number, y: number) {
+  const halfWidth = width() / 2
+  const halfHeight = height() / 2
+  const multiplier = coinflip() ? 1 : -1
+  return {
+    x: x + halfWidth * multiplier,
+    y: y + halfHeight * multiplier,
+  }
+}

src/helpers/index.ts

@@ -0,0 +1,2 @@
+export * from './chance'
+export * from './coordinates'

src/scenes/game.ts

@@ -1,30 +1,14 @@
 import { Scene } from '../constants'
 import { addEnemy, addPlayer } from '../gameobjects'
+import { outsideCoordinates } from '../helpers'
 
 scene(Scene.Game, () => {
   const player = addPlayer()
 
   add([text('Press arrow keys', { width: width() / 2 }), pos(12, 12)])
 
   loop(5, () => {
-    const { x, y } = coordinates(player.pos.x, player.pos.y)
+    const { x, y } = outsideCoordinates(player.pos.x, player.pos.y)
     addEnemy(x, y, player)
   })
 })
-
-/**
- * Random coordinates outside the camera view.
- */
-function coordinates(x: number, y: number) {
-  const halfWidth = width() / 2
-  const halfHeight = height() / 2
-  const multiplier = coinflip() ? 1 : -1
-  return {
-    x: x + halfWidth * multiplier,
-    y: y + halfHeight * multiplier,
-  }
-}
-
-function coinflip() {
-  return Boolean(randi(2))
-}