Apa iku fungsi tingkat dhuwur?

Question

Accepted Answer

A **higher-order function** adalah fungsi sing nindakake paling ora salah siji saka: **nampa fungsi minangka argument**, utawa **balik fungsi**. Kaya-kaya bisa amarga fungsi iku *first-class values* ing JS (sampeyan bisa ngirim-irim kaya value apa wae).

## Njajal fungsi

```js
[1, 2, 3].map(n => n * 2);        // map takes a function
button.addEventListener("click", handler); // so does addEventListener
setTimeout(() => doThing(), 1000);
```

## Balik fungsi (asring nggunakake closure)

```js
function multiplier(factor) {
  return n => n * factor;  // returns a function that remembers `factor`
}
const double = multiplier(2);
const triple = multiplier(3);
double(5); // 10
triple(5); // 15
```

Kene `multiplier` nggawe fungsi khusus saka fungsi umum — closure njejak `factor`.

## Conto praktis: wrapper logging

```js
function withLogging(fn) {
  return (...args) => {
    console.log(`calling with`, args);
    const result = fn(...args);
    console.log(`result`, result);
    return result;
  };
}
const loggedAdd = withLogging((a, b) => a + b);
```

## Kahanane

Fungsi tingkat dhuwur nggawe kode **deklaratif lan bisa balekake.

Kahanane ndukung cara array (`map`/`filter`/`reduce`), nangani acara, middleware, decorators, currying, lan pola React (HOCs, custom hooks).

Kajaba nulis logika loop sing padha bola-bali, sampeyan ngirim *tingkah laku* minangka fungsi.