Discussion on: 4 Must-Know TypeScript Tips & Tricks

I think I understand - so you're suggesting if we renamed size to count, this would cause issues?

Type-checking would catch that (the beauty of TypeScript!). In the below example, we pick the two properties to create the new Pizza type...

type Pizza = Pick<Consumable, "size" | "caloriesPerServing">;

const pepperoniPizza: Pizza = {
    size: "large",
    caloriesPerServing: 500
}

But if we renamed "size" to "count", as you suggested...

type Pizza = Pick<Consumable, "size" | "caloriesPerServing">;

const pepperoniPizza: Pizza = {
    count: "large",
    caloriesPerServing: 500
}

Then we would receive a type error at compile time on the pepperoniPizza declaration line, as the object's shape (Pizza) does not have the property count.

We could then perform the changes we require on our type:

type Pizza = Pick<Consumable, "count" | "caloriesPerServing">;

...which would resolve the issue.

Did that make sense? Hope that answers your question!