Apa iku hoisting?

Question

Apa iku hoisting?

Accepted Answer

**Hoisting** yaiku tingkah laku JavaScript sing ndelalang **declarations** menyang puncak scope-ne sajeroning fase compile, sadurunge kode apa pun mlaku. Nanging *cara* barang dhoisting beda-beda miturut jenis declaration.

```js
console.log(a); // undefined  — `var a` is hoisted & initialized to undefined
var a = 1;

foo();          // "works!" — function declarations are fully hoisted
function foo() { console.log("works!"); }

console.log(b); // ❌ ReferenceError — temporal dead zone
let b = 2;
```

## Apa sing dhoisting, lan carane

- **`var`**: declaration dhoisting lan diinisialake dadi `undefined`. Dadi maca dheweke suwene awal medali `undefined`, ora kudu error.
- **`function` declarations**: dhoisting lengkap — sampeyan bisa nglumpukake dheweke sadurunge baris definisine.
- **`let` / `const`**: dhoisting nanging **ora diinisialake**. Padha lungguh ing *Temporal Dead Zone* (TDZ) saka wiwit blok nganti baris deklarasine; ngakses dheweke ing TDZ nggegani `ReferenceError`.
- **Function expressions** (`const f = () => {}`) ora bisa diyakake suwene awal — mung `const`/`var` binding sing dhoisting, ora fungsi-ne.

## Mulane penting

Hoisting nerangake "mengapa iki `undefined`?" lan "mengapa nglumpukake fungsi iki sadurunge definisine bisa?" TDZ kanggo `let`/`const` tenan-tenan minangka *feature* — ngluwari silent `undefined` bugs dadi loud errors, nggugah sampeyan nglumpukake sadurunge nggunakake.