Create userscript.js

src/addons/addons/ScratchHighlightFullwidthNumber/userscript.js

@@ -0,0 +1,21 @@
+const target = document.querySelectorAll('.blocklyBlockCanvas');
+const regexp = /[０-９]/;
+
+const observer = new MutationObserver(records => {
+  document.querySelectorAll('*[data-argument-type~="text"] text, *[data-argument-type~="number"] text').forEach(e => {
+    if (regexp.test(e.textContent)){
+      e.style.fill = 'red';
+    } else {
+      e.style.fill = '';
+    }
+  });
+});
+
+target.forEach(e => {
+  observer.observe(e, {
+    attributes: true,
+    characterData: true,
+    childList: true,
+    subtree: true
+  });
+});