React-dnd what does $splice do
It's basically an immutable version of plain splice functions such as
newcards.splice(dragIndex, 1); // removing what you are dragging.newcards.splice(hoverIndex, 0, dragCard); // inserting it into hoverIndex.Instead of directly manipulating the target array, those Immutability Helpers are helping you update the state by creating and assigning a new state.
Took me a while to understand. Here is step by step explanation in conventional arrow function
moveCard = (dragIndex, hoverIndex) => { // list of cards let newcards = this.state.cards; // dragCard is card we are dragging let dragCard = newcards[dragIndex]; // removing this dragCard from array newcards.splice(dragIndex, 1); // insert dragCard at hover position newcards.splice(hoverIndex, 0, dragCard); // update State this.setState({ cards: newcards }); };