Mikroorm-nested-set NPM

MikroORM nested set

This package is an open source extension for MikroORM, which enables Nested Set Tree for your needs

Disclaimer

For now, this package doesn't support multiple trees, but it may change in near future

Installation

npm install mikroorm-nested-set

Setup

At first, you have to create a new entity-type class and extend NestedSetSubjectAbstract (Keep in mind that you have to pass your entity for generic type)

import {NestedSetSubjectAbstract} from "mikroorm-nested-set";
import {Cascade, Collection, Entity, ManyToOne, OneToMany, PrimaryKey, Property} from "@mikro-orm/core";

@Entity()
export class CategoryFake extends NestedSetSubjectAbstract<CategoryFake>{

    @PrimaryKey({ type: 'number' })
    id: number;

    @Property({ type: 'number' })
    left: number;

    @Property({ type: 'number' })
    right: number;

    @Property({ type: 'number' })
    depth: number;

    @OneToMany({
        entity: () => CategoryFake,
        mappedBy: category => category.parent,
        cascade: [Cascade.ALL],
        eager: true,
        orphanRemoval: true
    })
    children = new Collection<CategoryFake>(this)

    @ManyToOne({
        entity: () => CategoryFake
    })
    parent: CategoryFake

    getIdentifier(): number | string {
        return this.id
    }

    getIdentifierName(): string {
        return 'id'
    }

}

After that, you have to create a repository for your new entity. (It's required for extra tree methods)

import {NestedSetSubjectRepository} from "mikroorm-nested-set";
import {CategoryFake} from "./category.fake";

export class CategoryFakeRepository extends NestedSetSubjectRepository<CategoryFake> {}

Don't forget about migration file if you chose migration files way

Examples

Create new tree

const nestedSetNodeOperator = new NestedSetNodeOperator<Category>()

const mainCategory = new Category()
mainCategory.name = 'Main'
mainCategory.parent = null

const manCategory = new Category()
manCategory.name = 'man'

const womanCategory = new Category()
womanCategory.name = 'Woman'

nestedSetNodeOperator.addNode(manCategory, mainCategory, mainCategory)
nestedSetNodeOperator.addNode(womanCategory, mainCategory, mainCategory)

const famousShoesCategory = new Category()
famousShoesCategory.name = 'Famous shoes category'

const manJeans = new Category()
manJeans.name = 'Jeans'

nestedSetNodeOperator.addNode(manJeans, manCategory, mainCategory)
nestedSetNodeOperator.addNode(famousShoesCategory, womanCategory, mainCategory)

await this.categoryRepository.persistAndFlushTree(mainCategory)

Update existing tree (Be aware of the difference between readableTree and writableTree)

const writableTree = await this.categoryRepository.findWritableTree()
const nestedSetNodeOperator = new NestedSetNodeOperator<Category>()

const manShirtsCategory = new Category()
manShirtsCategory.name = 'man shirts'

const manShoesCategory = new Category()
manShirtsCategory.name = 'man shoes Category'


const nodeToRemove = nestedSetNodeOperator.findNodeInTree(writableTree, {
    getIdentifier(): number | string {
        return 124 // Just some random unneccessary category
    }
})

nestedSetNodeOperator.removeNode(nodeToRemove, writableTree)

const manCategory = nestedSetNodeOperator.findNodeInTree(writableTree, {
  getIdentifier(): number | string {
    return 2 // Man category
  }
})

nestedSetNodeOperator.addNode(manShirtsCategory, manCategory, writableTree)
nestedSetNodeOperator.addNode(manShoesCategory, manCategory, writableTree)

await this.categoryRepository.persistAndFlushTree(writableTree)

Find and edit node property

const writableTree = await this.categoryRepository.findWritableTree()
const nestedSetNodeOperator = new NestedSetNodeOperator<Category>()

// You can pass either whole object or object with getIdentifier implemanation
const nodeToEdit = nestedSetNodeOperator.findNodeInTree(writableTree, {
  getIdentifier(): number | string {
    return 124
  }
})

nodeToEdit.customProperty = '123'

await this.categoryRepository.persistAndFlushTree(writableTree)