// @skipLibCheck: true
// @lib: dom, es7

interface A {
    id: string
}

interface B {
    id: string
    fieldB: string
}

async function countEverything(): Promise<number> {
    const providerA = async (): Promise<A[]> => { return [] }
    const providerB = async (): Promise<B[]> => { return [] }

    const [resultA, resultB] = await Promise.all([
        providerA(),
        providerB(),
    ] as const);

    const dataA: A[] = resultA;
    const dataB: B[] = resultB;
    if (dataA && dataB) {
        return dataA.length + dataB.length;
    }
    return 0;
}
