Adonis Lucid Ordering

A simple way to maintain order with your Lucid models.

Introduction

This package provides a convenient mixin to create ordered behavior (sequences) with your Lucid models. This sequence order can be maintained at a per table level or via an ordered column.

Installation

npm i @adonify/lucid-ordering

# Or using Yarn

yarn add @adonify/lucid-ordering

Configuration

node ace configure @adonify/lucid-ordering

Usage

Add the mixin to any Lucid model

import { BaseModel } from "@ioc:Adonis/Lucid/Orm";
import { compose } from '@ioc:Adonis/Core/Helpers'
import { Ordered } from "@ioc:Adonify/LucidOrdering";

export default class Todo extends compose(BaseModel, Ordered) {}

Create the Todo migration or add an order field to your existing model.

The column must be called order, however it doesn't need to be an integer. Any datatype that supports equality comparison will work.

import BaseSchema from "@ioc:Adonis/Lucid/Schema";

export default class extends BaseSchema {
  protected tableName = "todos";

  public async up() {
    this.schema.createTable(this.tableName, (table) => {
      table.increments("id");
      table.timestamp("created_at", { useTz: true });
      table.timestamp("updated_at", { useTz: true });
      table.integer("order").notNullable(); // 👈 the column is needed 
    });
  }

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

Ordered models with respect to an order key

We often need to maintain different sequences on one table with respect to a unique field. For example we may have a Board model with Todo's that we need we need to keep in order corresponding to the Board's id.

You can do this using the orderKey() decorator as follows. You can use the decorator on multiple columns to create unique combinations to maintain order with, but be aware this results in extra queries under the hood.

import { BaseModel, BelongsTo, belongsTo, column } from "@ioc:Adonis/Lucid/Orm";
import Board from "App/Models/Board";
import { compose } from '@ioc:Adonis/Core/Helpers'
import { Ordered, orderKey } from "@ioc:Adonify/LucidOrdering";

export default class Todo extends compose(BaseModel, Ordered) {
  @column()
  @orderKey()
  public boardId: number;

  @belongsTo(() => Board)
  public board: BelongsTo<typeof Board>;
}

export default class extends BaseSchema {
  protected tableName = "todos";

  public async up() {
    this.schema.createTable(this.tableName, (table) => {
      table.increments("id");
      table.timestamp("created_at", { useTz: true });
      table.timestamp("updated_at", { useTz: true });
      table.integer("order").notNullable(); // 👈 order in the sequence 
      table
        .integer("board_id")
        .unsigned()
        .references("boards.id")
        .onDelete("CASCADE"); // 👈 key to track the sequence on the table 
    });
  }

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

Now the mixin will maintain separate sequences on the todos table based on the grouping of their boardId.

Creating new models

When a new ordered model is created the order will automatically be set to the largest number in the sequence + 1.

// Assume no todos are present in the database yet
const todo1 = await Todo.create({}) // will have order of 0 
const todo2 = await Todo.create({}) // will have order of 1

If you wish to manually set the order when you create a model, you can supply it and the order will not be auto-generated.

// Assume no todos are present in the database yet
const todo1 = await Todo.create({ order: 0 }) // will have order of 0 
const todo2 = await Todo.create({ order: 2 }) // will have order of 2 

With an order key

// Assume no todos are present in the database yet
const todo1 = await Todo.create({ boardId: 1 }) // will have order of 0 
const todo2 = await Todo.create({ boardId: 1 }) // will have order of 1

const todo3 = await Todo.create({ boardId: 2 }) // will have order of 0 
const todo4 = await Todo.create({ boardId: 2 }) // will have order of 1

Maintaining order

Deletes

When a model is deleted, the order of the sequence will be automatically synced.

// Assume no todos are present in the database yet
const todo1 = await Todo.create({}) 
const todo2 = await Todo.create({}) 
const todo3 = await Todo.create({}) 

await todo2.delete() 
// todo1 and todo3 will now be synced to have orders of 0 and 1 respectively 

Note

Models will only be automatically synced if you use the model delete() method as it relies on the afterDelete() hook under the hood.

Manually syncing orders

If your sequence were to ever become out of order, you can manually sync the sequence.

await todo.syncSequence()

This will sync all models in the sequence, with respect to any order keys present.

Warning

This package relies on keeping all models in an ordered sequence (ie. 1, 2, 3, ...n). If you manually update these values through the database, you will need to sync the sequence again for the various methods and hooks to work correctly.

Furthermore, this approach relies on potentially doing an update on each row of the sequence when a row is deleted, and on multiple rows during order moves. This means large datasets may not be optimal for your performance needs and you should use this package with caution.

Model functions

Issues

If you have a question or found a bug, feel free to open an issue.