1.21.7 • Public • Published



@onehat/data A robust ORM for Javascript. Can CRUD, search, sort, filter, paginate your data. Integrates with many front- and back-end storage mediums.

  • Repositories. A Repository stores many Entities in a storage medium. Corresponds to a database table. Repositories can sort, search/filter, and add/edit/delete their constituent Entities.
  • Storage Mediums. Repositories are specialized to store their data in a single type of storage medium. Available types of Repositories include: Memory, Ajax, Rest, LocalStorage (Browser), SessionStorage (Browser), IndexedDB (Browser), AsyncStorage (React Native/Expo), SecureStore (React Native/Expo). One special type of Repository—LocalFromRemote—combines two different Repository types (one local and one remote) into a single Repository, thereby allowing autosyncing between the local and remote repositories, enabling true offline-first capability.
  • Entities. An Entity is a single record of data, organized into properties. Corresponds to a database row. Entity data can be accessed directly (entity.username), via specific properties and their formatted values (entity.properties.username.displayValue), or by obtaining a JS object of the whole Entity (entity.getDisplayValues(), or entity.getSubmitValues()).
  • Properties. A Property is a single unit of data. Corresponds to a database field. Properties are differentiated into different Property types (e.g. Integer, String, Boolean, etc), and thereby allow for easy formatting of "display" or "submit" values. For example, a date might be set to display as "Wed, Feb 5, 2020" but submit as "2020-02-05".
  • Schemas. A Schema defines the configuration of a Repository. Corresponds roughly to the database table schema. The Schema defines the name and type of Repository, the Properties that exist, and which are "id" and "display" Properties.


npm i @onehat/data


Comprehensive unit tests can be found in ./cypress/integration. These are an excellent source of code examples. Comprehensive API documentation can be found in ./docs.

1. Define a Schema

For every type of Entity you will use (e.g. Users or Animals or Invoices), define a Schema. A Schema determines the various Properties that each Entity will have, as well as the medium where the Entities will be stored.

const Users = {
	name: 'Users',
	model: {
		idProperty: 'id',
		displayProperty: 'username',
		properties: [
			{ name: 'id', type: 'int', },
			{ name: 'username', type: 'string', }, // explicitly set property type
			{ name: 'password', }, // type: 'string' is assumed, if not explicitly set
			{ name: 'first_name', },
			{ name: 'last_name', },
			{ name: 'email', allowNull: false, }, // make it a required field
			{ name: 'last_login', type: 'datetime', defaultValue: 'now', }, // give it a default value.
		sorters: [
				name: 'last_name',
				direction: 'ASC',
				name: 'first_name',
				direction: 'ASC',
	repository: 'memory', // Repository type. Can be string name or config object
export default Users;

Every Property must have a unique name. All other attributes are optional. Common Property attributes include:

  • name - The name of the Property
  • type - The type of the Property (e.g. 'string', 'bool', 'int', etc)
  • allowNull - Is this Property required to have a value?
  • defaultValue - Default value for this Property if none is supplied
  • isSortable - Whether this Property type is sortable

Other Property attributes exist and can be found in the API.

2. Create a Repository

The easiest way to create one or more Repositories is to use the global oneHatData singleton object. Each schema will have a bound repository of the same name (e.g. "Users", or "Groups").

import oneHatData from '@onehat/data';
import Groups from './Groups';
import Users from './Users';

	.then(() => {
		const UsersRepository = oneHatData.getRepository('Users');

		// Do something with your data


3. Add / Edit / Delete an Entity

Once you have a Repository initialized, you can start adding data to it. Data is manipulated asynchronously, so you may optionally wait for it to complete.

const UsersRepository = oneHatData.getRepository('Users');

// 1. Add an Entity
const userEntity = await UsersRepository.add({
	username: 'ajones',
	password: '12345',
	first_name: 'Alice',
	last_name: 'Jones',
	email: 'alice@example.com',

// 2. Edit an Entity
// Use assignment to change the value of a particular Property.
userEntity.password = 'mypass';

// Or you can be more verbose about it

// 3. Delete an Entity

// Or delete it from the Repository
await UsersRepository.delete(userEntity);

4. Filter and Sort the Entities in a Repository

There are lots of filtering and sorting methods available on Repositories.

// Add a single filter
UsersRepository.filter('first_name', 'Alice');
const foundEntities = UsersRepository.entities;

// Or search by an id or function
const myEntity = UsersRepository.getById(1);
const results = UsersRepository.getBy((entity) => {
	return entity.id > 2;

// Sort the entities by a particular Property
UsersRepository.sort('last_name', 'DESC');
const sortedEntities = UsersRepository.entities;

5. Listen for events and respond to them

Repositories, Entities, and Properties emit many different kinds of events.

// The 'change' event, emitted from an Entity, is relayed through the Repository and becomes 'entity_change'
UsersRepository.on('entity_change', (entity) => {
	console.log('changed entity');
userEntity.first_name = 'Joe';
// prints 'changed entity' to console

// The 'changeData' event is fired from the Repository after multiple Entities are loaded at once
UsersRepository.on('changeData', (entities) => {
	console.log('entities changed');
	{ email: 'alice@example.com' },
	{ email: 'bob@example.com' },
	{ email: 'charlie@example.com' },
// prints 'entities changed' to console

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