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# `useStateList`
Provides handles for circular iteration over states list.
Supports forward and backward iterations and arbitrary position set.
## Usage
```jsx
import { useStateList } from 'react-use';
import { useRef } from 'react';
const stateSet = ['first', 'second', 'third', 'fourth', 'fifth'];
const Demo = () => {
const { state, prev, next, setStateAt, setState, currentIndex, isFirst, isLast } = useStateList(stateSet);
const indexInput = useRef<HTMLInputElement>(null);
const stateInput = useRef<HTMLInputElement>(null);
return (
<div>
<pre>
{state} [index: {currentIndex}], [isFirst: {isFirst}], [isLast: {isLast}]
</pre>
<button onClick={() => prev()}>prev</button>
<br />
<button onClick={() => next()}>next</button>
<br />
<input type="text" ref={indexInput} style={{ width: 120 }} />
<button onClick={() => setStateAt((indexInput.current!.value as unknown) as number)}>set state by index</button>
<br />
<input type="text" ref={stateInput} style={{ width: 120 }} />
<button onClick={() => setState(stateInput.current!.value)}> set state by value</button>
</div>
);
};
```
## Reference
```ts
const { state, currentIndex, prev, next, setStateAt, setState, isFirst, isLast } = useStateList<T>(stateSet: T[] = []);
```
If `stateSet` changed, became shorter than before and `currentIndex` left in shrunk gap - the last element of list will be taken as current.
- **`state`**_`: T`_ — current state value;
- **`currentIndex`**_`: number`_ — current state index;
- **`prev()`**_`: void`_ — switches state to the previous one. If first element selected it will switch to the last one;
- **`next()`**_`: void`_ — switches state to the next one. If last element selected it will switch to the first one;
- **`setStateAt(newIndex: number)`**_`: void`_ — set the arbitrary state by index. Indexes are looped, and can be negative.
_4ex:_ if list contains 5 elements, attempt to set index 9 will bring use to the 5th element, in case of negative index it will start counting from the right, so -17 will bring us to the 4th element.
- **`setState(state: T)`**_`: void`_ — set the arbitrary state value that exists in `stateSet`. _In case new state does not exists in `stateSet` an Error will be thrown._
- **`isFirst`**_`: boolean`_ — `true` if current state is the first one.
- **`isLast`**_`: boolean`_ — `true` if current state is the last one.
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