How to declare a specific type of empty array inside a object using typescript?

Question

In the above code, I want to declare an empty Ingredient array instead of ingredients: [ new Ingredient('Apple', '5')]

In the tutorial that I am doing, they don't show the case of the empty array. Is there a way to do it or do I always have to declare some values to let the angular know the type of the array?

Answer 1

You need to declare the type of your state:

type State = {
  ingredients: Ingredient[];
}

and then set the type of initialState to State :

const initialState: State = {
  ingredients: [],
}

Answer 2

There are many ways to do it really, try this:

let ingredients: Ingredient[] = [];
const initialState = {
    ingredients: ingredients
}

Not sure why you need to define it inside an object, but this will work.

Answer 3

This should also work

    const initialState = {
      ingredients: new Array<Ingredient>()
    };