# `Masu.Tree`
[🔗](https://github.com/hattoriai/masu/blob/v0.1.0/lib/masu/tree.ex#L1)

Rows in a tree: children with the columns of their parent, indented,
opened and closed.

    <.data_grid id="accounts" rows={@accounts} tree={:parent_id}>

`tree` names the field of a row that holds its parent's id (or is a
function of the row that gives it); a row whose parent is `nil`, or not
among the rows, is a root. The grid shows the roots, and the children
of each row the person opens, as one list: a tree of twenty thousand
rows scrolls as a list of twenty thousand rows does, a block at a time.

Sorting sorts the children of each row among themselves. A filter or a
search keeps the rows that match and their ancestors, so that a match is
never shown without the rows above it; while one is applied, the rows it
keeps are open, and the person may close them.

Both sources take `tree` (see `Masu.Source.List` and `Masu.Source.Ecto`).
A source of your own implements `c:Masu.Source.nodes/3`.

# `node_info`

```elixir
@type node_info() :: %{
  level: non_neg_integer(),
  children: boolean(),
  expanded: boolean(),
  position: pos_integer(),
  size: pos_integer()
}
```

Where a row is in the tree: its `level` (0 for a root), whether it has
`children`, whether it is `expanded`, its `position` among its siblings
(from 1) and how many siblings there are (`size`).

---

*Consult [api-reference.md](api-reference.md) for complete listing*