Perhaps a more suitable alternative:

type PredefinedFruits = "apples" | "oranges";

function selectFruit<T extends string>(fruit: T | PredefinedFruits) {

console.log(`You selected: ${fruit}`);

}

// Usage with predefined options

selectFruit("apples"); // Valid, and autocomplete will suggest "apples" and "oranges"

// Usage with any other string

selectFruit("bananas"); // Also valid, no autocomplete suggestion