React: update one item in a list without recreating all items

Question

Let\'s say I have a list of 1000 items. And I rendering it with React, like this:

class Parent extends React.Component {
  render() {
    // this.state.list is a         


        

Answer 1

you have to compare a item with your items

UpdateComment=(comment)=>{
    let objIndex = this.state.comments.findIndex((obj => obj.id === comment.id));

    let comments = [...this.state.comments];
    comments[objIndex].content = comment.content
    comments[objIndex].idea = comment.idea
    this.setState({comments});
  }