Generator Example 1

generator-example.jsx

import { range, map } from './utils.js';

let iter = range(0, 1000); // almost-zero memory & computation overhead!

let list = (
  <ul>
    {map(iter, n => <li key={n}>{n}</li>)
  </ul>
);

utils.js

export function range(start, end) {
  for (let i = start; i < end; i++) {
    yield i;
  }
}

export function map(iterable, mapper) {
  let result = [];
  let index = 0;
  for (let value of iterable) {
    result.push(mapper(value, index++));
  }
  return result;
}