Hari 8: ES6+ — Destructuring Lanjutan & Optional Chaining

Destructuring Lanjutan

// Nested destructuring
const { a: { b: { c } } } = { a: { b: { c: 42 } } };
console.log(c); // 42

// Swap dua variabel
let x = 1, y = 2;
[x, y] = [y, x];
console.log(x, y); // 2 1

// Parameter fungsi dengan destructuring
function tampilUser({ nama, umur = 0, alamat: { kota } = {} }) {
    return `${nama} (${umur}) — ${kota ?? "Unknown"}`;
}
const user = { nama: "Budi", umur: 25, alamat: { kota: "Jakarta" } };
console.log(tampilUser(user)); // Budi (25) — Jakarta

Optional Chaining & Nullish Coalescing

const config = {
    db: {
        host: "localhost",
        port: 5432,
    }
};

// Optional chaining (?.)
console.log(config?.db?.host);      // "localhost"
console.log(config?.cache?.ttl);    // undefined (tidak error)
console.log(config?.db?.user?.name); // undefined

// Nullish coalescing (??)
const port = config?.db?.port ?? 3000;
console.log(port); // 5432

// Logical Assignment (ES2021)
let a = null;
a ??= "default";  // a = a ?? "default"
console.log(a); // "default"