When SSG mode is added to a TypeScript project, Quasar creates /src-ssg/ssg-renderer.ts automatically. In an existing JavaScript setup, rename ssg-renderer.js to ssg-renderer.ts; Quasar discovers either extension.

The wrapper functions infer their callback and return types:

import { defineSsgGetPages } from '#q-app'
import routes from '@/router/routes'

export const getSsgPages = defineSsgGetPages(
  async ({ parseVueRouterRoutes }) => {
    const { ssgPages } = await parseVueRouterRoutes({ routes, verbose: true })
    return ssgPages
  }
)

Dependencies imported only by the renderer belong in /src-ssg/package.json. If a dependency does not include its own declarations, install its @types/* package there as a development dependency.