I've been using React for a while and I'm starting to incorporate Typescript into it. In my previous projects, I was used to creating large "container" objects like this:

```
const theme = {
  colors: {
    primary: '#00f',
    accent: '#f70',
  },
  sizes: {
    base: '16px',
  },
};

```

How could I define a type for such an object? It seems awkward that I have to define the interface by typing (pardon the pun) every single member of it, then repeat it all over to assign the values:

```
interface ThemeType { colors: ThemeColors, sizes: ThemeSizes }
interface ThemeColors { primary: string, accent: string }
interface ThemeSizes { base: string }

const theme : ThemeType = {
  // ...
};

```

Is there another way to do it? At least a more compact way?