The Nymph core provides the base level classes and utilities to query the database, save data to it, and define different data types.


npm install --save @nymphjs/nymph


To use Nymph, you need a database driver. Nymph.js provides a MySQL driver, PostgreSQL driver, and a SQLite3 driver. They all provide the exact same functionality.


Here's an overview:

// main.ts
import { Nymph } from '@nymphjs/nymph';
import MySQLDriver from '@nymphjs/driver-mysql';
import TodoClass from './Todo';

const mysqlConfig = {
  host: 'your_db_host',
  database: 'your_database',
  user: 'your_user',
  password: 'your_password',

// Create a new instance of Nymph.
const nymph = new Nymph({}, new MySQLDriver(mysqlConfig));
// addEntityClass returns the class you should use for this instance of Nymph.
const Todo = nymph.addEntityClass(TodoClass);

// You are set up. Now you can use entity classes like `Todo` to store data,
// and Nymph's query methods like `getEntities` to retrieve them.

async function run() {
  const myEntity = await Todo.factory();
  myEntity.text = 'Get it done!';
  await myEntity.$save();

  const otherPendingTodos = await nymph.getEntities(
    { class: Todo },
    { type: '&', '!guid': myEntity.guid, equal: ['done', false] },

  const total = otherPendingTodos.length;
  const single = total === 1;
    `Besides the one I just created, there ${
      single ? 'is' : 'are'
    } ${total} pending todo${single ? '' : 's'} in the database.`,
// Todo.ts
import { Entity } from '@nymphjs/nymph';

export type TodoData = {
  text: string;
  done: boolean;

export default class Todo extends Entity<TodoData> {
  static ETYPE = 'todo'; // This is used for the table name(s) in the DB.
  static class = 'Todo'; // This is used to map references to their class.

  constructor() {

    // Within the methods of an entity, you will use `this.$data` to access
    // its data. Outside, you don't need the $data part.
    this.$data.text = '';
    this.$data.done = false;

  async $getOtherTodos() {
    // this.$nymph (or this.nymph in a static function) is the instance of Nymph
    // this entity was loaded with. Creating transactions will create a new
    // instance of Nymph, so it could be a transactional instance.
    const otherTodos = await this.$nymph.getEntities(
      { class: Todo },
      { type: '!&', guid: this.guid },
    return otherTodos;


See the config declaration file.