The underlying type of the tree.
An updated zipper pointing at a new focus.
import {Zipper, from, of} from 'effect-tree'
import {pipe} from 'effect'
// ┬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 = pipe(tree, Zipper.fromTree, Zipper.head, Zipper.head)
const hop1 = Zipper.up(start)
expect(Zipper.getValue(hop1)).toBe(2)
const hop2 = Zipper.up(hop1)
expect(Zipper.getValue(hop2)).toBe(1)
// Out-of-bounds exception when nowhere left to go.
expect(() => Zipper.up(hop2)).toThrow(/getOrThrow/)
Navigate from a node to its parent or throw an exception if the focused node is a tree root. Unsafe version of tryUp.