export type ItemRO = { readonly id: string }
export type PriceRO = { readonly price: number }
export type QtyRO = { readonly qty: number }
export type ShippingRO = { readonly shipping: number }

T extends ItemQtyRO & TotalRO

type ItemRO = { readonly id: string }
function trololo(a: ItemRO) {
    console.log(a.id)
}

function trololo2(a: { id: string }) {
    console.log(a.id)
}

const myVar = {id: "5", trololo: "aa"}

trololo(myVar)
trololo2(myVar)

(property) total: <U extends ItemTotalRO, T extends ItemsRO<U>>(documents: readonly T[]) => U[]