React To-Do usuwanie notatki

import React from 'react';
import TodoItem from './TodoItem'

class Todo extends React.Component{
    state = {
        elements: [
            {id: '234544365', isComplited: true, title: 'Zrobić zakupy'},
            {id: '234553452', isComplited: false, title: 'Opłacić domenę'}

        ],
        inputValue: ''
    }

    markComplited(id){
        const index = this.state.elements.findIndex(x => x.id == id)
        const newElements = this.state.elements
        newElements[index].isComplited = true

        this.setState({elements: newElements})
    }

    addItem() {
        const item = {
            id: Math.random(),
            title: this.state.inputValue
        }
        const newElements = [item, ...this.state.elements]
        this.setState({elements: newElements})
        this.setState({inputValue: ''})
    }

    deleteItem()
    {
        console.log('usuwam')
    }

    inputHandler(event)
    {
        const newValue = event.target.value
        this.setState({inputValue: newValue})
    }
    
    

    render(){
        const elements = this.state.elements.map(e => {
            return <TodoItem element={e} markClicked={this.markComplited.bind(this)}  />
        })
        return(
            <div>
            Todo app
            <input type="text" value={this.state.inputValue} onChange={this.inputHandler.bind(this)}/>
            <button onClick={this.addItem.bind(this)}>Dodaj tekst</button>
            {elements}
            </div>
        ) 

        
    }
}

export default Todo;

import React from 'react';
import Todo from "./Todo";

const TodoItem = props => {
    return(
        <div className={`card ${props.element.isComplited ? 'complited': ''}`} key={props.element.id}>
            <h2>{props.element.title}</h2>
            <button onClick={() => props.markClicked(props.element.id)}>Zakończone</button>
            <button onClick={() => delete}>usuń</button>
        </div>
    )
}

export default TodoItem;

deleteItem()
   {
       console.log('usuwam')
   }

<TodoItem element={e} markClicked={this.markComplited.bind(this)} delete={this.deleteItem.bind(this)}  />

<button onClick={() => this.delete.bind(this)}>usuń</button>

<button onClick={() => this.props.delete)}>usuń</button>