fix: Make popup positioning wrap around

changelog.md

@@ -1,3 +1,7 @@
+## 0.5.1 (2021-04-19)
+
+- Make <kbd>j</kbd> / <kbd>k</kbd> keys wrap-around when they reach the limit.
+
 ## 0.5.0 (2021-04-17)
 
 - Adds ability to move the popup window using the <kbd>j</kbd> / <kbd>k</kbd>

src/content.ts

@@ -62,6 +62,7 @@ import {
   isTextInputNode,
 } from './dom-utils';
 import { SelectionMeta } from './meta';
+import { mod } from './mod';
 import { kanjiToNumber } from './numbers';
 import {
   CopyState,
@@ -423,15 +424,15 @@ export class RikaiContent {
       this.config.readingOnly = !this.config.readingOnly;
       this.showPopup();
     } else if (movePopupDown.includes(upperKey)) {
-      if (this.popupPositionMode < PopupPositionMode.End) {
-        this.popupPositionMode++;
-        this.showPopup();
-      }
+      this.popupPositionMode =
+        (this.popupPositionMode + 1) % (PopupPositionMode.End + 1);
+      this.showPopup();
     } else if (movePopupUp.includes(upperKey)) {
-      if (this.popupPositionMode > PopupPositionMode.Start) {
-        this.popupPositionMode--;
-        this.showPopup();
-      }
+      this.popupPositionMode = mod(
+        this.popupPositionMode - 1,
+        PopupPositionMode.End + 1
+      );
+      this.showPopup();
     } else if (
       navigator.clipboard &&
       // It's important we _don't_ enter copy mode when the Ctrl key is being

src/mod.ts

@@ -0,0 +1,4 @@
+// JS % operator is a _remainder_ operator
+export function mod(a: number, n: number): number {
+  return ((a % n) + n) % n;
+}