React change state of checkbox - reactjs

Question

Class component - list of items with a boolean property ; I've added onChange method to change state of this propery in a collection. When I try to compile I have:
Line 15:59: Array.prototype.map() expects a return value from arrow
function array-callback-return
import React from "react";
class ItemList extends React.Component {
constructor(props) {
super(props);
this.state = {
items: props.items
}
}
toggleCompleted = (position) => {
const updatedItems = this.state.items.map((item, idx) => {
position === idx ? {...item, completed: !item.completed} : item //err
})
this.setState({
items: updatedItems
})
}
render() {
return(
<div className="col-12 col-lg-8 mx-auto">
<h3 className="h3">Tasks</h3>
{this.state.items.length > 0 &&
<table className="table">
<thead>
<tr>
<th scope="col">#</th>
<th scope="col">Title</th>
<th scope="col">Description</th>
<th scope="col">Completed</th>
</tr>
</thead>
<tbody>
{this.state.items.map((item, idx) => {
return (
<tr key={idx+1}>
<th scope="row">{idx+1}</th>
<td>{item.title}</td>
<td>{item.description}</td>
<td>
<input
id={"completed".concat(idx)}
className="form-check-input"
type="checkbox"
checked={item.completed}
onChange={() => {this.toggleCompleted(idx)}}/>
</td>
</tr>
);
})}
</tbody>
</table>
}
</div>
)
}
}
export default ItemList;
Why?

Answer 1

Add missing return statement:
const updatedItems = this.state.items.map((item, idx) => {
return position === idx ? {...item, completed: !item.completed} : item
})
or remove {}
const updatedItems = this.state.items.map((item, idx) =>
position === idx ? {...item, completed: !item.completed} : item
)
Read more about basics here

Answer 2

Add a "return" before
position === idx ? {...item, completed: !item.completed} : item