text: let uidGen = 1;
  
  function uid() {
    return uidGen++;
  }
  
  function randomPercent() {
    return (Math.random() - 0.5) * 0.3;
  }
  
  function randomValue() {
    return Math.random() * 700;
  }
  
  function randomChars() {
    return (Math.random() + 1).toString(36).substring(2, 10);
  }
  
  function randomText(count) {
    return new Array(count).fill(0).map(randomChars).join();
  }
  
  function createItem() {
    return Object.freeze({
      key: '' + uid(),
      name: randomText(1),
      value: randomValue(),
      change: randomPercent()
    });
  }
  
  export function createItems(count) {
    return new Array(count).fill(0).map(createItem);
  }
  
  export function updateItems(items) {
    items.forEach((item, i) => {
      const change = randomPercent();
      items[i].value *= (1 + change);
      items[i].change = change;
    });
  }
  