renderItems.js

  renderItems () {
    if (this.items.length > 0) {
      const className = ['list-group'].concat(this.props.itemsClassList || []).join(' ')

      if (this.observer) {
        etch.getScheduler().getNextUpdatePromise().then(() => {
          const elements = Array.from(this.refs.items.children)

          // Use initially rendered last item's height as height of all fake item
          // Refering 1st item is bad idea, since 1st item tend to be rendered differently.
          // const heightForFakeItem = elements.slice(0, this.props.initialRenderItemCount).pop().offsetHeight + 'px'
          const heightForFakeItem = elements.slice(0, this.props.initialRenderItemCount).pop().scrollHeight + 'px'

          elements.slice(this.props.initialRenderItemCount).forEach(element => {
            element.style.height = heightForFakeItem
            this.observer.observe(element)
          })
        })
      }

      this.listItems = this.items.map((item, index) => {
        const selected = this.getSelectedItem() === item
        return $(ListItemView, {
          element: this.elementForItem(item, {selected, index}),
          selected: selected,
          onclick: () => this.didClickItem(index)
        })
      })

      return $.ol(
        {className, ref: 'items'},
        ...this.listItems
      )
    } else if (!this.props.loadingMessage && this.props.emptyMessage) {
      return $.span({ref: 'emptyMessage'}, this.props.emptyMessage)
    } else {
      return ""
    }
  }