Menene nau'i na haɗe da hadewa?

Question

Accepted Answer

A **haɗe** (`A | B`) yana nufin "A **ko** B." A **hadewa** (`A & B`) yana nufin "A **da** B a lokaci gida."

```ts
// Union — value is one of several types
type Status = "loading" | "success" | "error"; // string literal union
let s: Status = "loading"; // only these three allowed

function id(x: string | number) { /* x is string OR number */ }
```

## Aiki da haɗe: kana iya amfani da abin da yake gida kawai

```ts
function format(x: string | number) {
  // x.toFixed(2); // ❌ toFixed doesn't exist on string
  if (typeof x === "number") return x.toFixed(2); // ✅ narrowed to number
  return x.toUpperCase();                          // ✅ here it's a string
}
```

Kafin ka **damje** haɗe, kana iya samun ɗan lokaci da yake gida a kowane ɓangare na haɗe — compiler yana kariyarka.

## Hadewa — daidaita sifofin

```ts
type Name = { name: string };
type Age = { age: number };
type Person = Name & Age; // must have BOTH name and age

const p: Person = { name: "Ann", age: 30 }; // both required
```

Hadewa ana yin amfani da ita don daidaita/hadda nau'i na abin don (alal misali, ƙara props ga nau'i da yayi bayyana).

## Dalilin da ya sa haka mahimmanci

Haɗe tana yin yadda "daya daga cikin yiwuwar da yawa" — tushe na amfani da jiya ta halitta (alal misali hadde na bambanta don jiyan ragewa), ruwan aiki, da nau'i masu ƙulla (`T | null`).

Hadewa tana daidaita nau'i tare.

A jama'a, suna baje da tsarin nau'i na TypeScript sankarinsa don nuni da bayyanar ainihin bayanan da kyau.