# createAtom

Signature
`createAtom<T>(atom: Atom<T>): [Accessor<T>, SetterFn<T>]`

valdres-solid
Subscribe to and update an atom's value

Returns a Solid accessor and a setter function for an atom. The accessor is reactive — any `createEffect` or component render that reads it will re-run when the atom changes.

## Usage

```tsx
import { atom } from "valdres"
import { createAtom } from "valdres-solid"

const countAtom = atom(0)

function Counter() {
    const [count, setCount] = createAtom(countAtom)
    return (
        <div>
            <span>{count()}</span>
            <button onClick={() => setCount(c => c + 1)}>+</button>
        </div>
    )
}
```

## Returns

| Index | Type          | Description                                           |
| ----- | ------------- | ----------------------------------------------------- |
| `[0]` | `Accessor<T>` | Reactive accessor — call it to read the current value |
| `[1]` | `SetterFn<T>` | Function to update the atom's value                   |

## Updater function

The setter supports both direct values and updater functions:

```ts
setCount(42)              // Set directly
setCount(prev => prev + 1) // Update based on previous value
```

> **Note**
>
>
> If you only need to read the value, use [createValue](https://valdres.dev/solid/createValue) instead. If you only need the setter, use [createSetAtom](https://valdres.dev/solid/createSetAtom) to avoid subscribing to changes.

## See also

- [createValue](https://valdres.dev/solid/createValue) — read-only accessor (no setter)
- [createSetAtom](https://valdres.dev/solid/createSetAtom) — write-only (no subscription)
- [createResetAtom](https://valdres.dev/solid/createResetAtom) — reset to default value