A day difference v2

// Old Code
const newMap = e.props.map;

let arr = this.state.maps;
let i = 0;
let found = false;

while (!found && i < arr.length) {
  found = arr[i].name === newMap.name;
  i++;
}

if (found) {
    arr[i - 1].completed = !arr[i - 1].completed;
}

this.setState({
   maps: arr
});

// New Code
const items = this.state.maps;
changedMaps.forEach(map => {
    const i = items.map(m => m.name).indexOf(map.name);
    items[i].completed = !items[i].completed;
});
this.setState({ items });