Describe the bug

For AutoComplete components, we can use optionLabel to display a custom label in the suggestions and selected item.
This works fine when the suggestions are objects but it does not work properly when the suggestions are just strings. In that case, the selected item does not display the label provided by optionLabel but just the value itself, while with objects, the selected item displays the label generated by optionLabel.

Edit:
After some initial investigation of the source code, I saw in

So, apparently there is a workaround to fix this issue: Add an optionValue function that just returns the item itself, aka:

optionValue(item: any): any {
  return item;
}

Pull Request Link

#19076

Reproducer

https://stackblitz.com/edit/dz8njim1-jg7bfq1g?file=src%2Fapp%2Fautocomplete-objects-demo.html

Environment

PrimeNG 20.3.0, Angular 20, Firefox

Angular version

20.0.4

PrimeNG version

v20

Browser(s)

Firefox

Steps to reproduce the behavior

1. Go to https://stackblitz.com/edit/dz8njim1-jg7bfq1g?file=src%2Fapp%2Fautocomplete-objects-demo.html
2. The top AutoComplete uses an array of objects for the suggestions, while the bottom AutoComplete uses an array of strings
3. The optionLabel function is the same for both and just returns test
4. When we select and item in both AutoCompletes, the top one still displays test (which is intended behaviour) while the bottom one displays the actual value instead of test

Expected behavior

The selected item in AutoCopmlete component should always display the label generated by optionLabel no matter if the suggestions are objects or primitive types like strings.