[terra-form-select] Fix exception when no options exist. (#4079)

packages/terra-form-select/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+* Fixed
+  * Fixed exception thrown when down arrow is pressed on a form select with no options.
+
 ## 6.60.0 - (March 27, 2024)
 
 * Fixed

packages/terra-form-select/src/shared/_MenuUtil.js

@@ -194,6 +194,10 @@ class MenuUtil {
    */
   static findNext(object, value) {
     const options = MenuUtil.flatten(object, true);
+    if (options.length === 0) {
+      return null;
+    }
+
     const index = options.findIndex(({ props }) => MenuUtil.isEqual(props.value, value));
     if (options.length - 1 === index) {
       return options[0].props.value;

packages/terra-form-select/tests/jest/MenuUtil.test.jsx

@@ -323,6 +323,12 @@ describe('MenuUtil', () => {
     });
   });
 
+  it('should return null if there are no options', () => {
+    const options = [];
+
+    expect(MenuUtil.findNext(options, null)).toBeNull();
+  });
+
   describe('findPrevious', () => {
     it('should return the option after the value', () => {
       const options = [