Seneca Entity is a plugin for Seneca

Provides a simple Object-Relation Mapping over Seneca messages as a convenience API for manipulating data.

Any data store can then be accessed using the full power of Seneca messages.

seneca-entity

	This open source module is sponsored and supported by Voxgig.

Install

With npm:

$ npm install seneca-entity

With yarn:

$ yarn add seneca-entity

TypeScript

Implemented using TypeScript. Minimal types are provided by the package.

Quick Example

Please visit senecajs.org for a more complete overview and documentation of the Seneca framework.

Read the Understanding Data Entities tutorial for a step-by-step introduction to Seneca data entities.

1const Seneca = require('seneca')
2
3const seneca = Seneca() // Create a new instance of Seneca.
4  .use('entity')        // Use the seneca-entity plugin (Seneca will require it).
5  
6// Create an reusable instance of the `person` entity.
7const Person = seneca.entity('person')
8
9// Create a specific person instance.
10let alice = Person.make$()
11
12// Set some fields (assumes a NoSQL database, or a predefined table).
13// Properties with a final `$` are reserved for the Entity API methods.
14alice.name = 'Alice'
15alice.location = 'Wonderland'
16
17// Save your data. Seneca entity provides a default in-memory store,
18// which is very useful for fast unit tests.
19alice = await alice.save$()
20
21// The `alice` entity now has an `id` field.
22let alsoAlice = await Person.load$(alice.id)
23alsoAlice.location = 'Looking Glass'
24
25// The `alsoAlice` entity will be updated, not created, because
26// it has an `id` field. The save$ method both creates and updates.
27await alsoAlice.save$()
28
29// Entity methods can be chained (until they return a Promise).
30let lily = await Person
31    .make$({
32      name: 'Lily',
33      location: 'Looking Glass'
34    })
35    .save$()
36
37// The data$ method exports a JSON serializable verson of the entity
38// as a plain object.
39console.log(lily.data$())
40
41// The data$ method can alternatively set multiple fields.
42await lily
43  .data$({
44    game: 'chess'
45  })
46  .save$()
47
48// List all the person entities.
49let people = await Person.list$()
50
51// List only those person entities with field `game` equal to the string "chess".
52let players = await Person.list$({game: 'chess'})

Seneca Entity is inspired in part by the ActiveRecord pattern as implemented by Ruby on Rails.

Seneca Entity is not a full Object Relation Mapping. It is a convenience API over the Seneca action patterns:

• role:entity,cmd:load - .load$()
• role:entity,cmd:save - .save$()
• role:entity,cmd:list - .list$()
• role:entity,cmd:remove - .remove$()

This means that you can extend the "ORM" using the same message manipulation as with all Seneca messages, including sending them over the network to other microservices.

In particular, you can:

• Support pretty much any kind of database for a standard set of basic operations, extending the query syntax if necessary - @seneca/s3-store
• Easily define reusable business logic that assumes standard entities, but is still extensible - @seneca/user
• Add cross-cutting concerns without polluting your business logic - @seneca/allow
• Customize specific operations for specific entities by adding your own action patterns - seneca.message('role:entity,cmd:save,name:person', async function(msg) { ... })
• Expose most REST or GraphQL APIs as "databases" - @seneca/trello-provider
• Use different databases for different entities, see Mapping Entities to Data Stores
• Namespace and isolate entities as desired; entities have not just a name, but also an optional base (table namespace) and zone (good for strict multi-tenancy), to use as you see fit.

BUT, Seneca entity does not natively implement relations, and loads only the top level entity. Since relation mapping often leads to inefficient queries, this is not such a bad thing. When relations are needed, you can implement them manually by customizing the appropriate action patterns. Or you may find that denormalizing your data is more fun than you think.

More Examples

API

Contributing

Background

License

Copyright (c) 2012-2022, Richard Rodger and other contributors. Licensed under MIT.