Explain the concept and benefits of using the 'readonly' modifier in TypeScript classes or interfaces.

At its core, the readonly modifier is used to make properties of a class or an interface immutable after their initial assignment. This means once a property is set, usually in the constructor of a class, it cannot be reassigned. This is particularly useful in TypeScript, a language designed to provide a more structured approach to JavaScript's flexibility.

Now, let's talk about the benefits. First and foremost, using readonly enhances the predictability of your code. By ensuring that certain properties do not change after their initial setup, you can prevent a whole class of bugs related to unexpected state mutation. Moreover, it makes your intention clear to other developers who might work on your code, signaling...