What is destructuring and what can it do?

Question

Accepted Answer

**Destructuring** unpacks values from arrays or properties from objects into distinct variables in a single, readable statement.

```js
// array destructuring (by position)
const [first, second] = [10, 20];      // first=10, second=20
const [a, , c] = [1, 2, 3];            // skip the middle → a=1, c=3

// object destructuring (by name)
const { name, age } = user;
const { name: userName } = user;        // rename → userName
const { city = "Unknown" } = address;   // default if missing
```

## Powerful patterns

```js
// nested
const { address: { city } } = user;

// rest — grab the leftovers
const { id, ...rest } = obj;

// function parameters with defaults (very common)
function createUser({ name, role = "user" } = {}) { ... }

// swap variables without a temp
[x, y] = [y, x];
```

## Where you see it constantly

```js
// React
const [count, setCount] = useState(0);
function Card({ title, children }) { ... }

// imports, API responses
const { data, error } = await api.get("/users");
```

## Why it matters

Destructuring removes boilerplate (`const name = user.name; const age = user.age;` becomes one line), makes function signatures self-documenting (you see exactly which props are used), and is idiomatic in modern JS, React, and Node.

The default-value and rest features also make handling optional/partial data clean.