Wesleys Rocking StickyViewAbility Config.js

updateActive ({changed, viewableItems}) {
    let active = this.state.activeIndex
    let firstViewableItem = viewableItems[0].index
    let lastViewableItem = viewableItems[viewableItems.length - 1].index
    let nextState = {renderBottom: false, renderTop: false}

    if (active < firstViewableItem) {
      // Item is not viewable and should be rendered sticky on **top**
      nextState.renderTop = true

    } else if (active > lastViewableItem) {
      // Item is not viewable and should be rendered sticky on **bottom**
      nextState.renderBottom = true
    }

    this.setState(nextState)
  }

http://g.recordit.co/WuQVejsg7o.gif