type PathConverter<P> = (params: P) => string
type routes = {
  boards: {
    GET: {
      pathParams: {}
      bodyParams: {}
    },
    POST: {
      pathParams: {}
      bodyParams: { title: string }
    }
  },
  board: {
    GET: {
      pathParams: { id: number }
      bodyParams: {}
    },
    PATCH: {
      pathParams: { id: number }
      bodyParams: { title: string }
    }
  }
}
type HttpVerbs = 'GET' | 'POST' | 'PATCH'
type Verbs<R> = keyof R & HttpVerbs
type Resources = keyof routes

function f<
  V extends Verbs<routes[R]>,
  R extends Resources,
  P extends routes[R][V] extends { pathParams: infer PP, bodyParams: infer BP } ? PP & BP : {}
>(verb: V, name: R, params: P) {
  return verb + name + JSON.stringify(params)
}

const updateBoard = ['PATCH', 'board']
f('PATCH', 'board', { id: 1, title: 'hi' })