Tidy up code to normalize text, extract text helpers

app/javascript/controllers/filter_controller.js

@@ -1,5 +1,6 @@
 import { Controller } from "@hotwired/stimulus"
 import { debounce } from "helpers/timing_helpers"
+import { filterMatches } from "helpers/text_helpers"
 
 export default class extends Controller {
   static targets = [ "input", "item" ]
@@ -10,7 +11,7 @@ export default class extends Controller {
 
   filter() {
     this.itemTargets.forEach(item => {
-      if (this.#convertDiacritics(item.innerText).toLowerCase().includes(this.inputTarget.value.toLowerCase())) {
+      if (filterMatches(item.innerText, this.inputTarget.value)) {
         item.removeAttribute("hidden")
       } else {
         item.toggleAttribute("hidden", true)
@@ -19,8 +20,4 @@ export default class extends Controller {
 
     this.dispatch("changed")
   }
-
-  #convertDiacritics(text) {
-    return text.normalize("NFD").replace(/[\u0300-\u036f]/g, "")
-  }
 }

app/javascript/helpers/text_helpers.js

@@ -1,3 +1,13 @@
 export function isMultiLineString(string) {
   return /\r|\n/.test(string)
 }
+
+export function normalizeFilteredText(string) {
+  return string
+    .toLowerCase()
+    .normalize("NFD").replace(/[\u0300-\u036f]/g, "") // Remove diacritics
+}
+
+export function filterMatches(text, potentialMatch) {
+  return normalizeFilteredText(text).includes(normalizeFilteredText(potentialMatch))
+}