using a interface to type a anonymous object in typescript

Question

I have a Interface IBase and a variable that contains a few other objects (in the sample i just added base for a better demonstration)

interface IBase {
    height?:number;
    width?:number;
}

var element = {
    base: {

    }
}

How can I say that the object that the varable element.base has is from the type IBase? I know that I could create a type for the element variable that contains the types of base etc, but is that also a possibility to type that scenario without doing so.

Answer 1

Van den Brink's answer is good. Just as a demo another option :

var element = {
    base: <IBase> {

    }
}

This will give the desired intellisense as well :

Answer 2

If you change the declaration of var element to the following it knows what base is:

var element: { base: IBase; } = {
    base: {
    }
}

Note: you can also create a new interface for it like this which makes it a bit more reusable: interface IElement { base: IBase; } and then use it like here: var element: IElement = { base: {} }