Union and intersection types

In the previous section, we mentioned union types but haven't covered them as yet. Let's fix that right away – it will only be a small detour and will prove very useful later on!

Union types allow us to define new types by joining existing ones together using the | (pipe) character. When you use a union type, you can only access the members that are common to all those types in the union.

A great example is that you can use a union instead of any to indicate that you accept either one type or the other:

interface BoardGame { 
    name: string; 
    description: string; 
    minimalAge: number; 
    players: string; 
    duration: string; 
} 
 
interface VideoGame { 
    name: string;
    description: string; 
    minimalAge: number; 
    players: string; 
    online: boolean; 
} 
 
function displayGame(game: VideoGame | BoardGame...