move xxArrowPressed globals into the Input class

main.js

@@ -8,12 +8,6 @@ const Orientation = {
   RIGHT: 'right'
 }
 
-// TODO: make these not global.
-let upArrowPressed = false;
-let downArrowPressed = false;
-let leftArrowPressed = false;
-let rightArrowPressed = false;
-
 class Input {
   constructor() {
     this.up = false;
@@ -29,39 +23,44 @@ class Input {
     this.select = false;
     this.start = false;
 
+    this.upArrowPressed = false;
+    this.downArrowPressed = false;
+    this.leftArrowPressed = false;
+    this.rightArrowPressed = false;
+
     window.addEventListener('gamepadconnected', this.gamepadConnected);
     window.addEventListener('gamepaddisconnected', this.gamepadDisconnected);
-    document.addEventListener('keydown', this.keyDown);
-    document.addEventListener('keyup', this.keyUp);
+    document.addEventListener('keydown', (e) => this.keyDown(e));
+    document.addEventListener('keyup', (e) => this.keyUp(e));
   }
 
   keyDown(e) {
     if (e.key == 'ArrowUp' || e.key == 'w') {
-      upArrowPressed = true;
+      this.upArrowPressed = true;
     }
     if (e.key == 'ArrowDown' || e.key == 's') {
-      downArrowPressed = true;
+      this.downArrowPressed = true;
     }
     if (e.key == 'ArrowLeft' || e.key == 'a') {
-      leftArrowPressed = true;
+      this.leftArrowPressed = true;
     }
     if (e.key == 'ArrowRight' || e.key == 'd') {
-      rightArrowPressed = true;
+      this.rightArrowPressed = true;
     }
   }
 
   keyUp(e) {
     if (e.key == 'ArrowUp' || e.key == 'w') {
-      upArrowPressed = false;
+      this.upArrowPressed = false;
     }
     if (e.key == 'ArrowDown' || e.key == 's') {
-      downArrowPressed = false;
+      this.downArrowPressed = false;
     }
     if (e.key == 'ArrowLeft' || e.key == 'a') {
-      leftArrowPressed = false;
+      this.leftArrowPressed = false;
     }
     if (e.key == 'ArrowRight' || e.key == 'd') {
-      rightArrowPressed = false;
+      this.rightArrowPressed = false;
     }
   }
 
@@ -69,10 +68,10 @@ class Input {
     // TODO: have a config screen instead of hard-coding the 8Bitdo SNES30 pad.
     // TODO: handle connects / disconnects more correctly.
 
-    this.up = upArrowPressed;
-    this.down = downArrowPressed;
-    this.left = leftArrowPressed;
-    this.right = rightArrowPressed;
+    this.up = this.upArrowPressed;
+    this.down = this.downArrowPressed;
+    this.left = this.leftArrowPressed;
+    this.right = this.rightArrowPressed;
 
     const gamepad = navigator.getGamepads()[0];
     if (gamepad == null || !gamepad.connected || gamepad.axes.length < 2 ||