AdonisJS Nested Set

Nested set model implementation for AdonisJS, similar to laravel-nestedset for Laravel.

This package provides efficient tree operations using the Nested Set Model algorithm.

Installation

npm install adonisjs-nested-set

Usage

1. Create Migration

import { BaseSchema } from '@adonisjs/lucid/schema'
import { addNestedSetColumns } from 'adonisjs-nested-set'

export default class extends BaseSchema {
  protected tableName = 'categories'

  async up() {
    this.schema.createTable(this.tableName, (table) => {
      table.increments('id')
      table.string('name').notNullable()

      // Add nested set columns (_lft, _rgt, parent_id)
      addNestedSetColumns(table)

      table.timestamps(true, true)
    })
  }

  async down() {
    this.schema.dropTable(this.tableName)
  }
}

2. Create Model

import { BaseModel, column } from '@adonisjs/lucid/orm'
import { applyNestedSet } from 'adonisjs-nested-set'

class Category extends BaseModel {
  static table = 'categories'

  @column({ isPrimary: true })
  declare id: number

  @column()
  declare name: string

  @column({ columnName: 'parent_id' })
  declare parentId: number | null

  @column({ columnName: '_lft' })
  declare _lft: number

  @column({ columnName: '_rgt' })
  declare _rgt: number
}

// Apply nested set functionality to the model
// The function returns properly typed model with all nested set methods
const CategoryWithNestedSet = applyNestedSet(Category)

// Export the typed model
// TypeScript automatically infers all nested set methods with proper types
export default CategoryWithNestedSet

3. Use in Your Code

Inserting Nodes

// Create root node
const root = await Category.create({ name: 'Root' })
await Category.fixTree()

// Create child node
const child = await Category.create({ name: 'Child', parentId: root.id })
await Category.fixTree()

// Or use appendTo method
const child2 = new Category()
child2.name = 'Child 2'
await child2.appendTo(root)
await Category.fixTree()

Retrieving Nodes

// Get all roots
const roots = await Category.roots().exec()

// Get a node
const node = await Category.find(1)

if (node) {
  // Static methods - called on Category class
  const ancestors = await Category.ancestorsOf(node).exec()
  const ancestorsAndSelf = await Category.ancestorsAndSelf(node).exec()
  const descendants = await Category.descendantsOf(node).exec()
  const descendantsAndSelf = await Category.descendantsAndSelf(node).exec()
  const siblings = await Category.siblingsOf(node).exec()
  const siblingsAndSelf = await Category.siblingsAndSelf(node).exec()

  // Instance methods - called on node instance
  const nodeAncestors = await node.ancestors().exec()
  const nodeDescendants = await node.descendants().exec()
  const nodeChildren = await node.children().exec()
  const nodeParent = await node.parent()
}

Building Tree

// Convert to tree structure
const nodes = await Category.all()
const tree = nodes.toTree()

// Convert to flat tree (children immediately after parent)
const flatTree = nodes.toFlatTree()

// Get subtree
const root = await Category.find(rootId)
const subtree = await Category.descendantsAndSelf(rootId).exec()
const treeStructure = subtree.toTree()

Helper Methods

const node = await Category.find(1)

if (node) {
  // Check node properties
  const isRoot = node.isRoot() // Check if node is root
  const isLeaf = node.isLeaf() // Check if node is leaf

  const other = await Category.find(2)
  if (other) {
    const isDescendant = node.isDescendantOf(other) // Check if node is descendant
    const isAncestor = node.isAncestorOf(other) // Check if node is ancestor
    const isChild = node.isChildOf(other) // Check if node is child
    const isSibling = node.isSiblingOf(other) // Check if node is sibling
  }

  const depth = await node.getDepth() // Get depth of node
}

Checking Consistency

// Check if tree is broken
const isBroken = await Category.isBroken()

// Get error statistics
const errors = await Category.countErrors()
// Returns: { oddness, duplicates, wrong_parent, missing_parent }

// Fix tree structure
await Category.fixTree()

Query Constraints

const node = await Category.find(1)

if (node) {
  // Where ancestor of
  const result = await Category.whereAncestorOf(node).exec()
  const result2 = await Category.whereAncestorOrSelf(node).exec()

  // Where descendant of
  const result3 = await Category.whereDescendantOf(node).exec()
  const result4 = await Category.whereDescendantOrSelf(node).exec()

  // Get nodes with depth
  const nodesWithDepth = await Category.withDepth().exec()
  nodesWithDepth.forEach((node) => {
    console.log(`Node ${node.name} is at depth ${node.$extras.depth}`)
  })
}

Deleting Nodes

// Delete a node - automatically deletes all descendants
const node = await Category.find(1)
await node.delete() // This will also delete all child nodes

// The delete method is automatically overridden to perform cascade deletion

API Reference

Static Methods

• Category.roots() - Get all root nodes
• Category.ancestorsOf(node) - Get ancestors of a node
• Category.ancestorsAndSelf(node) - Get ancestors including self
• Category.descendantsOf(node) - Get descendants of a node
• Category.descendantsAndSelf(node) - Get descendants including self
• Category.siblingsOf(node) - Get siblings of a node
• Category.siblingsAndSelf(node) - Get siblings including self
• Category.whereAncestorOf(node) - Where ancestor of
• Category.whereAncestorOrSelf(node) - Where ancestor or self
• Category.whereDescendantOf(node) - Where descendant of
• Category.whereDescendantOrSelf(node) - Where descendant or self
• Category.withDepth(as?) - Get nodes with depth information (depth stored in $extras.depth)
• Category.isBroken() - Check if tree is broken
• Category.countErrors() - Count errors in tree
• Category.fixTree() - Fix tree structure
• Category.getLftName() - Get left column name (default: '_lft')
• Category.getRgtName() - Get right column name (default: '_rgt')
• Category.getParentIdName() - Get parent ID column name (default: 'parent_id')

Instance Methods

• node.isRoot() - Check if node is root
• node.isLeaf() - Check if node is leaf
• node.isDescendantOf(other) - Check if node is descendant
• node.isAncestorOf(other) - Check if node is ancestor
• node.isChildOf(other) - Check if node is child
• node.isSiblingOf(other) - Check if node is sibling
• node.getDepth() - Get depth of node
• node.siblings() - Get siblings query
• node.ancestors() - Get ancestors query
• node.descendants() - Get descendants query
• node.children() - Get children query
• node.parent() - Get parent node
• node.makeRoot() - Make node a root
• node.appendTo(parent) - Append node to parent
• node.delete() - Delete node and all its descendants (cascade delete)

Collection Methods

• collection.toTree() - Convert collection to tree structure
• collection.toFlatTree() - Convert collection to flat tree

Migration Helpers

• addNestedSetColumns(table, lftColumn?, rgtColumn?, parentIdColumn?) - Add nested set columns
• dropNestedSetColumns(table, lftColumn?, rgtColumn?, parentIdColumn?) - Drop nested set columns

Important Notes

Cascade Deletion

When you delete a node using node.delete(), all its descendants are automatically deleted as well. This is handled automatically by the package.

Column Names

The package uses the following default column names:

• _lft - Left boundary
• _rgt - Right boundary
• parent_id - Parent node ID (in database)
• parentId - Parent node ID (in model, camelCase)

Make sure to specify columnName in your model decorators if your database uses different naming:

@column({ columnName: 'parent_id' })
declare parentId: number | null

@column({ columnName: '_lft' })
declare _lft: number

@column({ columnName: '_rgt' })
declare _rgt: number

SQLite Compatibility

When using SQLite, use integer instead of unsignedInteger in migrations:

table.integer('_lft').nullable()
table.integer('_rgt').nullable()
table.integer('parent_id').nullable()

TypeScript Support

Type Inference

The package provides full TypeScript support with automatic type inference - no configuration needed!

1. Static Methods: The applyNestedSet() function returns a properly typed model. All static methods like ancestorsOf(), descendantsOf(), etc. automatically accept model instances without type assertions.

2. Instance Methods: Instance methods are automatically typed via module augmentation for LucidRow (included in the package). Methods like children(), isRoot(), etc. work without any type assertions.

3. Query Results: Methods like find(), create(), first(), etc. automatically return instances with nested set methods included in their types.

Example with Full Type Safety

import Category from '#models/category'

// Static methods work without type assertions - automatic type inference!
const node = await Category.find(1)
if (node) {
  // ✅ All methods work without type assertions
  const ancestors = await Category.ancestorsOf(node).exec()
  const descendants = await Category.descendantsOf(node).exec()
  const children = await node.children().exec()
  const isRoot = node.isRoot()
  const isLeaf = node.isLeaf()
}

Key Benefits

• ✅ Zero Configuration: No need for declaration merging files or manual type assertions
• ✅ Full Type Safety: All methods are properly typed with correct return types
• ✅ IntelliSense Support: Full autocomplete for all nested set methods
• ✅ Type Inference: TypeScript automatically infers correct types for model instances

Testing

The package includes comprehensive unit tests. Run them with:

npm test

For integration tests with real database operations use AdonisJS application.

License

MIT