Function resolveDefaultThemeId

resolveDefaultThemeId(themes: unknown): string | null
Resolves the id of the theme a profile starts on.
Parameters
- themes: unknown
  A profile's themes block, as the profile or a themes.json carries it: { defaultTheme?, config?: { defautTheme? }, themes?: [{ id, … }] }. Anything else counts as a profile without themes.
Returns string | null
The declared default when it names a theme of the list (defaultTheme, then the legacy config.defautTheme); otherwise the first theme that has an id; null when the list holds no theme with an id.
Example
```
resolveDefaultThemeId({ themes: [{ id: "day" }, { id: "night" }] }); // "day"
resolveDefaultThemeId({ defaultTheme: "night", themes: [{ id: "day" }, { id: "night" }] }); // "night"
resolveDefaultThemeId({}); // null
```
- Defined in packages/core/src/kernel/config/default-theme.ts:59