Custom slider in react, Swiping images effecting all product images when next arrow btn pressed

I created function to swipe selected product image inside slide with left and right arrow btns. but when clicked it is swiping every item image not single one. i could not use newSlideArray variable outside of the function. can anyone explain me how to swipe single item image in slide ?

Here is my source code:

class ViewCart extends Component {
  constructor(props){
    super(props);
    this.state = {
      index: 0
    }
  nextSlide =(item)=> {
    let newSlideArray = [];
    item.gallery.map(img => newSlideArray.push(img))
    if(this.state.index === (newSlideArray.length - 1)){
      this.setState({
        index: 0
      })
    }else{
      this.setState({
        index: this.state.index + 1
      })
    } 
  } 
render() {
    return (
        {this.props.cart.map((item, index) => (
          <div>
              <div className={styles.slide}>
                <div className={styles.leftArrow} onClick={()=> {this.previousSlide(item)}}>← 
                <div className={styles.rightArrow} onClick={()=> {this.nextSlide(item)}}>→
                <img src={item.gallery[this.state.index]} alt="" />
              </div>
          </div>
        ))}
      </div>
    );
  }
}

[![enter image description here][1]][1]

here is. When right arrow pressed it is swiping every product image to the right not single one. [1]: https://i.stack.imgur.com/Xw0ME.png

Answer

You have to keep the picture index for each item. I’m using functional style for simplicity.

const [indexes, setIndexes] = useState({});

Asuming the item has an id:

const nextSlide = (item) => {
  const curIndex = indexes[item.id] || 0;
  const newIndex = curIndex === item.gallery.length - 1 ? 0 : curIndex + 1;
  setIndexes({ ...indexes, [item.id]: newIndex });
};

And then:

<img src={item.gallery[indexes[item.id] || 0]} alt="" />

Working example