capture keys on both keypress and keydown

src/components/content-input.js

@@ -2,12 +2,31 @@ import messages from '../content/messages';
 
 export default class ContentInputComponent {
   constructor(target) {
+    this.pressed = {};
+
     target.addEventListener('keypress', this.onKeyPress.bind(this));
     target.addEventListener('keydown', this.onKeyDown.bind(this));
     target.addEventListener('keyup', this.onKeyUp.bind(this));
   }
 
   onKeyPress(e) {
+    this.capture(e);
+  }
+
+  onKeyDown(e) {
+    this.capture(e);
+  }
+
+  onKeyUp(e) {
+    this.pressed[e.key] = false;
+  }
+
+  capture(e) {
+    if (this.pressed[e.key]) {
+      return;
+    }
+    this.pressed[e.key] = true;
+
     if (e.target instanceof HTMLInputElement ||
       e.target instanceof HTMLTextAreaElement ||
       e.target instanceof HTMLSelectElement) {
@@ -22,10 +41,4 @@ export default class ContentInputComponent {
       ctrl: e.ctrlKey
     });
   }
-
-  onKeyDown() {
-  }
-
-  onKeyUp() {
-  }
 }