ustk-todolist/react/src/components/Input.js

import * as React from 'react';
import PropTypes from 'prop-types';

function Input(props) {
  let input;

  function submit() {
    if (input.value.trim() !== '') {
      props.onClick(input.value);
    }
    input.value = '';
  }

  return (
    <div id="inputs">
      <input
        ref={node => {
          input = node;
        }}
        id="input"
        type="text"
      />
      <button id="add" onClick={() => submit()}>
        add
      </button>
    </div>
  );
}

Input.propTypes = {
  onClick: PropTypes.func.isRequired,
};

export default Input;