onRemovePhone.jsx

class PhoneList extends Component {
  
  onRemovePhone(phone) {
    fetch(`${this.props.apiUrl}/${phone.id}`, {
      method: "delete", 
      credentials: "same-origin"
    }).then(() => {
       this.setState(state => ({ phones: state.phones.filter(p => p.id != phone.id) }))
    })
    
    
    //...
}