How to know whether we are at first "li"

[PrimeObjects]

<button className={inList ? '' : 'disabled'} onClick={() => {this.call(increaseItemDepth)}}>

In the sample code, we can disabled the button by checking inList. If we are at the first "li", we should also disable the button because it will do nothing to increaseItemDepth, how can we know whether we are at the first "li"?

Thanks lot
Gary

[Soreine]

Here is a dumb solution: check for value.document === value.change.call(increaseItemDepth ...).document.

---

Or maybe the plugin could expose a function:

// If the given node is inside a list, returns all the ancestor lists as well as the 
// item index sequence in each of these list that leads to the given node.
function getPositionInList(document: Slate.Document, key: string): ?ListPosition

type ListPosition = {
  // The conceptual sequence of item index that leads to the current node
  path: List<number>
  ancestors: List<Slate.Block>
}

So you could

const listPosition = listPlugin.getPositionInList(document, key)
const isFirstItem = listPosition && listPosition.path.last() === 0