How to update an object in an array of Objects using setState

Question

I am using React, my state is defined as an array of object. I need to be able to change only one specific element in the state.data array, example object with id 1.

I would like to know:

• what is the proper way how to use setState() in this scenario.

constructor(props) {
  super(props);
  this.state = {
    data: [{
        id: 0,
        title: 'Buy a',
        status: 0, // 0 = todo, 1 = done
      },
      {
        id: 1,
        title: 'Buy b',
        status: 0,
      },
      {
        id: 2,
        title: 'Buy c',
        status: 0,
      }
    ]
  };
  this.onTitleChange = this.onTitleChange.bind(this);
}
onTitleChange(id, title) {
  console.log(id, title);
  debugger
}

Answer 1

You can get do a cloning of the state object using spread operator and then find the index of object in array with a given id using findIndex method Modify the object and set the state.

constructor(props) {
  super(props);
  this.state = {
    data: [{
        id: 0,
        title: 'Buy a',
        status: 0, // 0 = todo, 1 = done
      },
      {
        id: 1,
        title: 'Buy b',
        status: 0,
      },
      {
        id: 2,
        title: 'Buy c',
        status: 0,
      }
    ]
  };
  this.onTitleChange = this.onTitleChange.bind(this);
}
onTitleChange(id, title) {
   var data = [...this.state.data];
   var index = data.findIndex(obj => obj.id === id);
   data[index].title = title;
   this.setState({data});
}