routie dev init since i didn't adhere to any proper guidance up until now

frontend/node_modules/eslint-plugin-perfectionist/dist/utils/compare/build-string-formatter.js

@@ -0,0 +1,51 @@
+import { UnreachableCaseError } from '../unreachable-case-error.js'
+/**
+ * Creates a function that formats strings for comparison.
+ *
+ * Applies transformations based on the provided options:
+ *
+ * - Case normalization (lowercase if ignoreCase is true)
+ * - Special character handling (keep, trim, or remove)
+ * - Whitespace removal (always applied).
+ *
+ * @param params - Parameters for string formatting.
+ * @param params.ignoreCase - Whether to convert strings to lowercase.
+ * @param params.specialCharacters - How to handle special characters:
+ *
+ *   - 'keep': Keep all characters as-is
+ *   - 'trim': Remove leading special characters
+ *   - 'remove': Remove all special characters.
+ *
+ * @returns Function that formats a string for comparison.
+ * @throws {UnreachableCaseError} If an unknown special characters option is
+ *   specified.
+ */
+function buildStringFormatter({ specialCharacters, ignoreCase }) {
+  return value => {
+    let valueToCompare = value
+    if (ignoreCase) {
+      valueToCompare = valueToCompare.toLowerCase()
+    }
+    switch (specialCharacters) {
+      case 'remove':
+        valueToCompare = valueToCompare.replaceAll(
+          /[^a-z\u{C0}-\u{24F}\u{1E00}-\u{1EFF}]+/giu,
+          '',
+        )
+        break
+      case 'trim':
+        valueToCompare = valueToCompare.replaceAll(
+          /^[^a-z\u{C0}-\u{24F}\u{1E00}-\u{1EFF}]+/giu,
+          '',
+        )
+        break
+      case 'keep':
+        break
+      /* v8 ignore next 2 -- @preserve Exhaustive guard. */
+      default:
+        throw new UnreachableCaseError(specialCharacters)
+    }
+    return valueToCompare.replaceAll(/\s/gu, '')
+  }
+}
+export { buildStringFormatter }