Ni ipi ndio aina za data za primitives katika JavaScript?

Question

Accepted Answer

JavaScript ina **aina 7 za primitives**, na kila kitu kingine (arrays, functions, objects) ni **object**.

Primitives: `string`, `number`, `boolean`, `null`, `undefined`, `bigint`, `symbol`.

```js
typeof "hi";       // "string"
typeof 42;         // "number"  (both ints and floats)
typeof true;       // "boolean"
typeof undefined;  // "undefined"
typeof 10n;        // "bigint"
typeof Symbol();   // "symbol"
typeof null;       // "object"  ← famous historical bug!
typeof {};         // "object"
typeof [];         // "object"  (arrays are objects)
typeof function(){};// "function"
```

## Mambo mawili ambayo yamaanisha

**1. Primitives haibadiliki na kuiga kwa thamani; objects huiga kwa reference.**

```js
let a = 5; let b = a; b++;          // a is still 5 (independent copies)
let x = {n:1}; let y = x; y.n = 2;  // x.n is now 2 (same object!)
```

**2. `typeof null === "object"`** ni hitilafu ya lugha ya muda mrefu ambayo lazima ukumbuke — ili kuangalia null, linganisha moja kwa moja (`x === null`).

## Kwa nini inastahili

Kuelewa thamani-vs-reference inaeleza kwa nini kubadilisha object iliyoshirikiwa inaathiri "zote" variables, kwa nini `{} === {}` ni `false`, na kwa nini unakili objects (spread) kabla ya kuzirekebisha katika UI zinazotumia state kama React.