Apa bedane antara interface lan type?

Question

IT Interview Practice · Accepted Answer

Loro-lorone nerangake wujude data lan asring bisa diakoni, nanging wae duwe kakmampuan beda.

```ts
interface User { name: string; age: number; }
type User2 = { name: string; age: number; };
```

## Apa sing bisa ```ts
type ID = string | number;          // unions
type Pair = [number, number];        // tuples
type Name = User["name"];            // indexed/mapped/conditional types
type Nullable<T> = T | null;         // wrap any type
``` dilakoni interface

`type` minangka **alias** umum kanggo tipe apa wae — primitif, union, tuple, mapped type. `interface` mung nerangake wujude obyek/fungsi.

## Apa sing bisa `interface` dilakoni type ora bisa

```ts
interface Box { width: number; }
interface Box { height: number; } // declaration merging — both merge into one
// Box now has width AND height
```

Interface ndhukung **declaration merging** (pirang-pirang deklarasi kombina) lan cara idiomatik kanggo extend/augment, kasuwen augment tipe pustaka pihak katelu.

## Sintaks extension

```ts
interface Admin extends User { role: string; }      // interface
type Admin2 = User & { role: string };               // type uses intersection
```

## Ngendi kudu dienggo

Konvensi umum: enggo `interface` kanggo wujude obyek lan API publik (pesan kesalahan luwih apik, bisa diext, bisa digabung), lan `type` yen sampeyan butuh union, tuple, utawa operasi tipe liyane. Pilih siji minangka baku kanggo konsistensi — akeh tim baku `interface` kanggo obyek lan ngalih `type` mung yen kakuwatan ambane dibutuhake.

Apa sing bisa ```ts

Sintaks extension

Ngendi kudu dienggo

Pitakon sing gegandhengan