List with dynamic columns

<!DOCTYPE html>
<html>
  <head>
    <script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-virtualized/dist/umd/react-virtualized.js"></script>

    <link rel="stylesheet" href="https://unpkg.com/react-virtualized/styles.css">
    <link rel="stylesheet" href="styles.css">
  </head>

  <body>
    <div id="example">
      <!-- This element's contents will be replaced with your code... -->
    </div>
    <script src="script.js"></script>
  </body>

</html>

const { AutoSizer, List } = ReactVirtualized

const ITEMS_COUNT = 98
const ITEM_SIZE = 100

// Render your list
ReactDOM.render(
  <AutoSizer>
    {({ height, width }) => {
      const itemsPerRow = Math.floor(width / ITEM_SIZE);
      const rowCount = Math.ceil(ITEMS_COUNT / itemsPerRow);
      
      return (
        <List
          className='List'
          width={width}
          height={height}
          rowCount={rowCount}
          rowHeight={ITEM_SIZE}
          rowRenderer={
            ({ index, key, style }) => {
              const items = [];
              const fromIndex = index * itemsPerRow;
              const toIndex = Math.min(fromIndex + itemsPerRow, ITEMS_COUNT);

              for (let i = fromIndex; i < toIndex; i++) {
                items.push(
                  <div
                    className='Item'
                    key={i}
                  >
                    Item {i}
                  </div>
                )
              }

              return (
                <div
                  className='Row'
                  key={key}
                  style={style}
                >
                  {items}
                </div>
              )
            }
          }
        />
      )
    }}
  </AutoSizer>,
  document.getElementById('example')
)

html, body, #example {
  height: 100%;
  margin: 0;
  padding: 0;
}
.List {
  border: 1px solid black;
  box-sizing: border-box;
}
.Row {
  width: 100%;
  height: 100%;
  border-bottom: 1px solid black;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  padding: 0 0.5rem;
  box-sizing: border-box;
}
.Item {
  width: 100px;
  height: 100px;
  display: inline-flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  border: 1px solid #eee;
}