https://github.com/0phoff/unist-util-walker

Walk unist trees with enter and leave functions
https://github.com/0phoff/unist-util-walker

ast syntax-tree traverse tree unifiedjs unist unist-util visit walk

Last synced: about 2 months ago
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Walk unist trees with enter and leave functions

• Host: GitHub
• URL: https://github.com/0phoff/unist-util-walker
• Owner: 0phoff
• License: mit
• Created: 2022-07-07T15:54:33.000Z (over 2 years ago)
• Default Branch: master
• Last Pushed: 2022-07-11T13:02:25.000Z (over 2 years ago)
• Last Synced: 2024-10-19T20:57:42.627Z (2 months ago)
• Topics: ast, syntax-tree, traverse, tree, unifiedjs, unist, unist-util, visit, walk
• Language: TypeScript
• Homepage:
• Size: 23.4 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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# UNIST UTIL WALKER

_Talk the Talk - Walk the Tree_  

[![npm version](https://img.shields.io/npm/v/unist-util-walker?color=blue&logo=npm)](https://www.npmjs.com/package/unist-util-walker)

[![npm downloads](https://img.shields.io/npm/dt/unist-util-walker?color=blue&logo=nodedotjs)](https://www.npmjs.com/package/unist-util-walker)

[![main](https://github.com/0phoff/unist-util-walker/actions/workflows/main.yml/badge.svg)](https://github.com/0phoff/unist-util-walker/actions/workflows/main.yml)

[![codecov](https://codecov.io/gh/0phoff/unist-util-walker/branch/master/graph/badge.svg?token=JWVVNRI6IK)](https://codecov.io/gh/0phoff/unist-util-walker)



Inspired by [estree-walker](https://github.com/Rich-Harris/estree-walker), this package provides a method to walk unist trees, by providing an `enter` and `leave` function.

The main advantage over [unist-util-visit](https://github.com/syntax-tree/unist-util-visit) is that we can enter all child nodes and accumulate data,

which we can then use in the leave function of the parent.

## Installation

This package is ESM only: Node 12+ is needed to use it and it must be imported instead of required.

### NPM

```bash

npm install unist-util-walker

```

### YARN

```bash

yarn add unist-util-walker

```

### PNPM

```bash

pnpm add unist-util-walker

```

## Usage

```typescript

import type { Node, Parent } from 'unist';

import { walk } from 'unist-util-walker';

import { u } from 'unist-builder';

const tree: Node = u('root', [

  u('subtree', {id: 1}),

  u('subtree', {id: 2}, [

    u('node', [u('leaf', {id: 1}), u('leaf', {id: 2})]),

    u('leaf', {id: 3}),

    u('void'),

  ]),

]);

walk(tree, {

  enter(node: Node, parent?: Parent, index?: number) {

    // some code happens

  },

  leave(node: Node, parent?: Parent, index?: number) {

    // some code happens

  }

});

```

Inside of the `enter` and `leave` functions, you can call the following functions:

- `this.break()`  

  Skips children and the leave function of the current node (only useful in enter).

- `this.skip()`  

  Skips children, but still runs the leave function of the current node (only useful in enter).

- `this.remove()`  

  Removes the node from the tree (has no effect on root node).

- `this.replace(node: Node)`  

  Replaces the node with a new one.