class TodoApp extends React.Component {
  render() {
    return (
      <div>
        <button onClick={this.handleClick}>
          ADD
        </button>
        <input onChange={this.handleInput}/>
        {
          this.state.todos.map((item) => {
            return (
              <li onClick={this.handleRemove(item.id)}>
                {item.text}
              </li>
            );
          });
        }
      </div>
    )
  }

// Property Initializer Syntax
  handleClick = () => {
    // "this"
  }

  handleInput = (e) => {
    // "this", "e"
  }

    // use closure to pass in additional arguments
  handleRemove = (id) => (e) => {
    // "this", "e", "id"
  }
}