1Step1: Inside state
2state = {
3 todos: [
4 {
5 id: 1,
6 title: "Eat breakfast",
7 completed: false
8 },
9 {
10 id: 2,
11 title: "Make bed",
12 completed: false
13 }
14 ]
15}
16
17Steps: Inside function where you need to update the value
18const elementsIndex = this.state.todos.findIndex(element => element.id == id );
19
20let newArray = [...this.state.todos]
21
22newArray[elementsIndex] = {...newArray[elementsIndex], completed: !newArray[elementsIndex].completed}
23
24this.setState({ todos: newArray });