The underlying type of the tree.
An updated zipper pointing at a new focus.
import {Zipper, from, of} from 'effect-tree'
// ┬1
// ├┬2
// │├─3
// │└─4
// └┬5
// ├─6
// └─7
const tree = from(1, from(2, of(3), of(4)), from(5, of(6), of(7)))
const start = Zipper.fromTree(tree)
const hop1 = Zipper.head(start)
expect(Zipper.getValue(hop1)).toBe(2)
const hop2 = Zipper.head(hop1)
expect(Zipper.getValue(hop2)).toBe(3)
// Out-of-bounds exception when nowhere left to go.
expect(() => Zipper.head(hop2)).toThrow(/getOrThrow/)
Navigate from a node to its first child or throw an exception if the focused node is a Leaf. Unsafe version of tryHead.