Fix inverted Ctrl+right/left handling in RTL fields (again) (#2191)

ts/editable/ContentEditable.svelte

@@ -14,7 +14,11 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     import type { MirrorAction } from "../sveltelib/dom-mirror";
     import type { SetupInputHandlerAction } from "../sveltelib/input-handler";
     import type { ContentEditableAPI } from "./content-editable";
-    import { preventBuiltinShortcuts, useFocusHandler } from "./content-editable";
+    import {
+        fixRTLKeyboardNav,
+        preventBuiltinShortcuts,
+        useFocusHandler,
+    } from "./content-editable";
 
     export let resolve: (editable: HTMLElement) => void;
 
@@ -40,6 +44,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     use:resolve
     use:setupFocusHandling
     use:preventBuiltinShortcuts
+    use:fixRTLKeyboardNav
     use:mirrorAction={mirrorOptions}
     use:inputHandlerAction={{}}
     on:focus

ts/editable/content-editable.ts

@@ -5,6 +5,7 @@ import type { SelectionLocation } from "../domlib/location";
 import { restoreSelection, saveSelection } from "../domlib/location";
 import { placeCaretAfterContent } from "../domlib/place-caret";
 import { bridgeCommand } from "../lib/bridgecommand";
+import { getSelection } from "../lib/cross-browser";
 import { on, preventDefault } from "../lib/events";
 import { isApplePlatform } from "../lib/platform";
 import { registerShortcut } from "../lib/shortcuts";
@@ -138,6 +139,38 @@ export function preventBuiltinShortcuts(editable: HTMLElement): void {
     }
 }
 
+declare global {
+    interface Selection {
+        modify(s: string, t: string, u: string): void;
+    }
+}
+
+// Fix inverted Ctrl+right/left handling in RTL fields
+export function fixRTLKeyboardNav(editable: HTMLElement): void {
+    editable.addEventListener("keydown", (evt: KeyboardEvent) => {
+        if (window.getComputedStyle(editable).direction === "rtl") {
+            const selection = getSelection(editable)!;
+            let granularity = "character";
+            let alter = "move";
+            if (evt.ctrlKey) {
+                granularity = "word";
+            }
+            if (evt.shiftKey) {
+                alter = "extend";
+            }
+            if (evt.code === "ArrowRight") {
+                selection.modify(alter, "right", granularity);
+                evt.preventDefault();
+                return;
+            } else if (evt.code === "ArrowLeft") {
+                selection.modify(alter, "left", granularity);
+                evt.preventDefault();
+                return;
+            }
+        }
+    });
+}
+
 /** API */
 
 export interface ContentEditableAPI {

ts/editor/base.ts

@@ -11,7 +11,6 @@ import "../sveltelib/export-runtime";
 
 declare global {
     interface Selection {
-        modify(s: string, t: string, u: string): void;
         addRange(r: Range): void;
         removeAllRanges(): void;
         getRangeAt(n: number): Range;