Use trimmed value for duplicate check in createOptions (#77)

The `createOptions` function was using `inputValue` to check for existing options, but `trimmedValue` to create new ones. This caused duplicates when `inputValue` had trailing spaces (e.g. "foo ") because it wouldn't match "foo" but would then create "foo".

Updates `exists` check to use `trimmedValue`, ensuring consistent behavior.

Also add a release note in CHANGELOG.md.

Author: google-labs-jules[bot]

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+- Fix a bug where `createOptions` could create duplicate options if the input
+  value had trailing whitespace (e.g. "foo "). The existence check now uses the
+  trimmed input value, consistent with the creation logic.
+
 ## [0.15.0] - 2024-07-06
 
 A focus on improving the ergonomics of `createOptions` to cover more use cases

src/create-options.tsx

@@ -134,7 +134,7 @@ const createOptions = (
     if (config.createable !== undefined) {
       const trimmedValue = inputValue.trim();
       const exists = createdOptions.some((option) =>
-        areEqualIgnoringCase(inputValue, option.text),
+        areEqualIgnoringCase(trimmedValue, option.text),
       );
 
       if (trimmedValue) {