tree-crawl

tree-crawl

n-ary tree traversal library.

tree-crawl is a lightweight tree crawler, well, technically walker.

It lets your walk n-ary trees in pre-order or post-order and does not 💥 when you mutate the tree while traversing it.

Install

npm install --save tree-crawl

Usage

import crawl from 'tree-crawl'

// traverse the tree in pre-order
crawl(tree, console.log)
crawl(tree, console.log, { order: 'pre' })

// traverse the tree in post-order
crawl(tree, console.log, { order: 'post' })

// traverse the tree using `childNodes` as the children key
crawl(tree, console.log, { childrenKey: 'childNodes' }

// skip a node and its children
crawl(tree, (node, context) => {
  if ('foo' === node.type) {
    context.skip()
  }
})

// break the walk
crawl(tree, (node, context) => {
  if ('foo' === node.type) {
    context.break()
  }
})

// remove a node
crawl(tree, (node, context) => {
  if ('foo' === node.type) {
    context.parent.children.splice(context.index, 1)
    context.remove()
  }
})

// replace a node
crawl(tree, (node, context) => {
  if ('foo' === node.type) {
    const node = {
      type: 'new node',
      children: [
        { type: 'new leaf' }
      ]
    }
    context.parent.children[context.index] = node
    context.replace(node)
  }
})

API

See the api documentation.

Related

• tree-mutate n-ary tree mutation library.
• tree-morph n-ary tree morphing library.

License

MIT © Nicolas Gryman