Javascript – How to specify type for multiple properties inside of an object?

I have this prop that I’ll be passing down:

checkboxesState

its original value is an empty object

{}

but it will change when user clicks on checkboxes, so it can look like this:

{
 "option1": true,
 "option2": true,
 "option3": true,
 "option4": true,
 ...
 ...
}

My question is, How can I define its type in the interface?

I have this but I have a feeling it’s missing something:

interface FieldProps {
   checkboxState: { [key: string]: boolean };
}