chore: make enemy follow player

src/constants/index.ts

@@ -0,0 +1 @@
+export * from './tags'

src/constants/tags.ts

@@ -0,0 +1,3 @@
+export enum Tag {
+  'player' = 'player',
+}

src/gameobjects/enemy.ts

@@ -1,5 +1,21 @@
+import { Tag } from '../constants'
 import { ghosty } from '../sprites'
 
+const ENEMY_SPEED = 200
+
 export function addEnemy(x: number, y: number) {
-  return add([ghosty, pos(x, y), anchor('center')])
+  const enemy = add([ghosty, pos(x, y), anchor('center')])
+
+  enemy.onUpdate(() => {
+    const player = get(Tag.player)[0]
+
+    if (!player) {
+      return
+    }
+
+    const dir = player.pos.sub(enemy.pos).unit()
+    enemy.move(dir.scale(ENEMY_SPEED))
+  })
+
+  return enemy
 }

src/gameobjects/player.ts

@@ -1,5 +1,15 @@
+import { Tag } from '../constants'
+import { addCursorKeys } from '../events'
 import { bean } from '../sprites'
 
 export function addPlayer(x = center().x, y = center().y) {
-  return add([bean, pos(x, y), rotate(0), anchor('center')])
+  const player = add([bean, pos(x, y), rotate(0), anchor('center'), Tag.player])
+
+  player.onUpdate(() => {
+    player.angle += 120 * dt()
+  })
+
+  addCursorKeys(player)
+
+  return player
 }

src/scenes/game.ts

@@ -1,15 +1,8 @@
-import { addCursorKeys } from '../events'
 import { addEnemy, addPlayer } from '../gameobjects'
 import { Scene } from '../types'
 
 scene(Scene.game, () => {
-  const player = addPlayer()
-
-  player.onUpdate(() => {
-    player.angle += 120 * dt()
-  })
-
-  addCursorKeys(player)
+  addPlayer()
 
   onClick(() => addKaboom(mousePos()))