Moved classes his own files

Key.js

@@ -0,0 +1,24 @@
+class Key {
+    constructor(onKeydown) {
+        this._pressed = {};
+        this.cb_onKeydown = onKeydown;
+
+        window.addEventListener('keydown', e => this.onKeydown(e));
+        window.addEventListener('keyup', e => this.onKeyup(e));
+    }
+
+    setKeydown(fn) {
+        this.cb_onKeydown = fn;
+    }
+
+    isDown(keyCode) {
+        return this._pressed[keyCode];
+    }
+    onKeydown(event) {
+        this._pressed[event.code] = true;
+        if (this.cb_onKeydown) this.cb_onKeydown(event);
+    }
+    onKeyup(event) {
+        delete this._pressed[event.code];
+    }
+}