2 files changed, 35 insertions, 5 deletions

diff --git a/ext/bg/js/anki-note-builder.js b/ext/bg/js/anki-note-builder.js
index b6114e4b..094dd77b 100644
--- a/ext/bg/js/anki-note-builder.js
+++ b/ext/bg/js/anki-note-builder.js
@@ -22,6 +22,7 @@
 class AnkiNoteBuilder {
     constructor({renderTemplate}) {
         this._renderTemplate = renderTemplate;
+        this._markerPattern = /\{([\w-]+)\}/g;
     }
 
     async createNote({
@@ -98,6 +99,12 @@ class AnkiNoteBuilder {
         return false;
     }
 
+    containsAnyMarker(field) {
+        const result = this._markerPattern.test(field);
+        this._markerPattern.lastIndex = 0;
+        return result;
+    }
+
     getRootDeckName(deckName) {
         const index = deckName.indexOf('::');
         return index >= 0 ? deckName.substring(0, index) : deckName;
@@ -136,8 +143,7 @@ class AnkiNoteBuilder {
     }
 
     async _formatField(field, data, templates, errors=null) {
-        const pattern = /\{([\w-]+)\}/g;
-        return await this._stringReplaceAsync(field, pattern, async (g0, marker) => {
+        return await this._stringReplaceAsync(field, this._markerPattern, async (g0, marker) => {
             try {
                 return await this._renderTemplate(templates, data, marker);
             } catch (e) {
diff --git a/ext/bg/js/settings/anki-controller.js b/ext/bg/js/settings/anki-controller.js
index 77b4ce96..b382bf26 100644
--- a/ext/bg/js/settings/anki-controller.js
+++ b/ext/bg/js/settings/anki-controller.js
@@ -17,6 +17,7 @@
 
 /* global
  * AnkiConnect
+ * AnkiNoteBuilder
  * ObjectPropertyAccessor
  * SelectorObserver
  */
@@ -25,6 +26,9 @@ class AnkiController {
     constructor(settingsController) {
         this._settingsController = settingsController;
         this._ankiConnect = new AnkiConnect();
+        this._ankiNoteBuilder = new AnkiNoteBuilder({
+            renderTemplate: null
+        });
         this._selectorObserver = new SelectorObserver({
             selector: '.anki-card',
             ignoreSelector: null,
@@ -159,6 +163,10 @@ class AnkiController {
         }
     }
 
+    containsAnyMarker(field) {
+        return this._ankiNoteBuilder.containsAnyMarker(field);
+    }
+
     // Private
 
     async _onOptionsChanged({options: {anki}}) {
@@ -403,8 +411,15 @@ class AnkiCardController {
         this._setModel(e.currentTarget.value);
     }
 
-    _onFieldChange(e) {
-        this._ankiController.validateFieldPermissions(e.currentTarget.value);
+    _onFieldChange(index, e) {
+        const node = e.currentTarget;
+        this._ankiController.validateFieldPermissions(node.value);
+        this._validateField(node, index);
+    }
+
+    _onFieldInput(index, e) {
+        const node = e.currentTarget;
+        this._validateField(node, index);
     }
 
     _onFieldMenuClosed({currentTarget: node, detail: {action, item}}) {
@@ -421,6 +436,13 @@ class AnkiCardController {
         this._setFieldMarker(link, link.textContent);
     }
 
+    _validateField(node, index) {
+        if (index === 0) {
+            const containsAnyMarker = this._ankiController.containsAnyMarker(node.value);
+            node.dataset.invalid = `${!containsAnyMarker}`;
+        }
+    }
+
     _setFieldMarker(element, marker) {
         const input = element.closest('.anki-card-field-value-container').querySelector('.anki-card-field-value');
         input.value = `{${marker}}`;
@@ -482,7 +504,9 @@ class AnkiCardController {
             const inputField = content.querySelector('.anki-card-field-value');
             inputField.value = fieldValue;
             inputField.dataset.setting = ObjectPropertyAccessor.getPathString(['anki', this._cardType, 'fields', fieldName]);
-            this._fieldEventListeners.addEventListener(inputField, 'change', this._onFieldChange.bind(this), false);
+            this._fieldEventListeners.addEventListener(inputField, 'change', this._onFieldChange.bind(this, index), false);
+            this._fieldEventListeners.addEventListener(inputField, 'input', this._onFieldInput.bind(this, index), false);
+            this._validateField(inputField, index);
 
             const markerList = content.querySelector('.anki-card-field-marker-list');
             if (markerList !== null) {