Examples

Running

Stackblitz

Has containers ready to run the examples.

Locally

You can run the examples locally. For example to run the basic example clone this repository, and launch the example:

git clone git@github.com:middle-ages/effect-tree.git
cd effect-tree
pnpm i
pnpm run:example draw

# Run with no parameters to get a list of examples
pnpm run:example

# This should work the same 
pnpm tsx examples/draw.ts

Browsing

The expected terminal output of each example appears inline with the source code.

Example	Note
basic	Create a tree, add/remove nodes, and other basic use-cases.
codecs	Encode/decode the same tree through all codecs.
directory-tree	Read directories into trees and write directories from trees.
draw	Draw trees in various themes.
fibonacci	A fold and an unfold all about the Fibonacci sequence.
folds	Fusing folds into tuples and structs.
genealogy	Level labels, bottom grounded subtrees, and encoding to indented strings.
generate	Enumerate and generate trees.
layout	Alternate tree layouts using the `Draw` module.
nary	N-ary trees: trees with a fixed degree.
unfolds	Unfold a tree from functions.
zipper	Use a zipper to navigate and change trees.

REPL

Running pnpm repl (or tsx dev/repl.ts) will run the Node.js REPL with symbols useful for quick experimentation added to the global scope.

Type help for more info. You should see this:

> tsx --import=./dev/repl.ts
» Loaded “dev/repl.ts”.

• .help............Node.js help
• help.............this help message
• _................previous result
• demoTree.........a small tree of strings
• getValue(tree)...get root node value
• draw(tree).......draw string or numeric tree to console
• of('hello')......create leaf from value
• from(............create tree from value and possibly empty tree list
       'root',
       of('leaf₁'),                               •┬─root
       from('branch', of('leaf₂'), of('leaf₃')) ┄→ ├───leaf₁
      )      ┊    ┊  ┊                        ┊    └─┬─branch
             ╰┄┬┄┄╯  ╰┄┄┄┄┄┄┄┄┄┄┬┄┄┄┄┄┄┄┄┄┄┄┄┄╯      └─┬─leaf₂
  branch value┄╯                ╰┄list of leaves       └─leaf₃

Try: > draw(demoTree)                  Global namespace:
     > pipe(8, binaryTree, draw)       ‣ effect exports under “effect”
                                       ‣ effect/Function exports
                                       ‣ effect-tree exports

Welcome to Node.js v22.14.0.
Type ".help" for more information.
>

Here is a screenshot of REPL run:

REPL Run