Add target=blank to links in formatted text via js

app/javascript/controllers/index.js

@@ -16,9 +16,11 @@ application.register("collapse-chevron-toggler", CollapseChevronTogglerControlle
 import HelloController from "./hello_controller"
 application.register("hello", HelloController)
 
+import RichTextLinkTargetsController from "./rich_text_link_targets_controller"
+application.register("rich-text-link-targets", RichTextLinkTargetsController)
+
 import SetThemeController from "./set_theme_controller"
 application.register("set-theme", SetThemeController)
 
 import ThemeSwitcherController from "./theme_switcher_controller"
 application.register("theme-switcher", ThemeSwitcherController)
-

app/javascript/controllers/rich_text_link_targets_controller.js

@@ -0,0 +1,12 @@
+import { Controller } from "@hotwired/stimulus"
+
+// Connects to data-controller="rich-text-link-targets"
+export default class extends Controller {
+  connect() {
+    this.element.querySelectorAll('div.trix-content a').forEach(function(link) {
+      if (link.host !== window.location.host) {
+        link.target = "_blank"
+      }
+    })
+  }
+}