Example 1

example1.jsx

import * as React from 'react';

const Note = props => (
  <div
    style={{ color: props.selectedNoteIndex === props.index ? 'red' : 'blue' }}
  >
    {props.note}
  </div>
);

const notes = [];
const selectedNoteIndex = 1;

notes.map((note, index) => (
  <Note note={note} index={index} selectedNoteIndex={selectedNoteIndex} />
));