Hari 10: Promise & Async/Await

Promise — Menangani Operasi Async

// Membuat Promise
const ambilData = new Promise((resolve, reject) => {
    const berhasil = true;
    setTimeout(() => {
        if (berhasil) resolve({ nama: "Budi", umur: 25 });
        else reject(new Error("Gagal mengambil data"));
    }, 1000);
});

// Menggunakan Promise
ambilData
    .then(data => console.log(data.nama))  // "Budi"
    .catch(err => console.error(err.message))
    .finally(() => console.log("Selesai"));

Async/Await — Lebih Bersih

async function simulasiAPI(id) {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            if (id > 0) resolve({ id, nama: `User ${id}`, aktif: true });
            else reject(new Error("ID tidak valid"));
        }, 100);
    });
}

async function main() {
    try {
        const user = await simulasiAPI(5);
        console.log(`User: ${user.nama}`);

        const [u1, u2] = await Promise.all([simulasiAPI(1), simulasiAPI(2)]);
        console.log(`${u1.nama} & ${u2.nama}`);
    } catch (err) {
        console.error("Error:", err.message);
    }
}
main();