use key-queue for input

src/background/key-queue.js

@@ -0,0 +1,28 @@
+import * as keys from './keys';
+import * as actions from '../shared/actions';
+
+const DEFAULT_KEYMAP = [
+  { keys: [{ code: KeyboardEvent.DOM_VK_K }], action: [ actions.SCROLL_UP, 1 ]},
+  { keys: [{ code: KeyboardEvent.DOM_VK_J }], action: [ actions.SCROLL_DOWN, 1 ]},
+  { keys: [{ code: KeyboardEvent.DOM_VK_H }], action: [ actions.TABS_PREV, 1 ]},
+  { keys: [{ code: KeyboardEvent.DOM_VK_L }], action: [ actions.TABS_NEXT, 1 ]},
+]
+
+export default class KeyQueue {
+
+  constructor(keymap) {
+    this.data = [];
+    this.keymap = keymap;
+  }
+
+  push(key) {
+    this.data.push(key);
+    for (let map of DEFAULT_KEYMAP) {
+      if (keys.keysEquals(map.keys, this.data)) {
+        this.data = [];
+        return map.action
+      }
+    }
+    return null;
+  }
+}