New type: ENUM

[bajtos]

Implement a new property type - enum (enumeration).

Example model definition:

{
  "name": "Person",
  "properties": {
    "sex": {
      "type": "enum",
      "values": ["male", "female", "other"]
    }
  }
}

Example remoting argument definition:

{
  accepts: { 
    arg: 'sex', type: 'enum', values: ['male', 'female', 'other'],
    http: { source: 'query' }
  }
}

Implementation details:

• support both "string" and "number" as a backing datatype
• strong-remoting should validate and coerce enumeration types
• loopback-datasource-juggler should validate property values of enum type
• connectors should map enum type to appropriate database counterpart
  • SQL connectors - see https://github.com/strongloop-internal/scrum-loopback/issues/603
  • MongoDB - see https://github.com/strongloop-internal/scrum-loopback/issues/604
• loopback-swagger should emit correct json-schema descriptor for enum properties
• autodiscovery

[raymondfeng]

Instead of introducing a new type, I would prefer to add a enum constraint to model properties, such as:

color: {
  type: 'string',
  enum: ['red', 'green', 'blue', ...]
}

It's similar as https://github.com/hapijs/joi#anyvalidvalue---aliases-only-equal

[bajtos]

Instead of introducing a new type, I would prefer to add a enum constraint to model properties

Sounds good 👍

[violet-day]

+1

[bajtos]

FWIW, we already have ENUM validation implemented via MyModel.validatesInclusionOf('gender', {in: ['male', 'female', 'other']});

I guess we only need to map enum property flag to validatesInclusionOf and implement support for enum in strong-remoting.

[ainesophaur]

+1

Would these additions then translate to loopback explorer? It'd be nice to show the allowed values.

[billinghamj]

+1

[gausie]

👍

[Bramanga]

👍

[ezraroi]

+1

[MyNameIsURL]

+1

[terehov]

+1

[parvbhullar]

+1

[sudomf]

+1

[geoand]

+1

[riteshjagga]

+1

[ataraxus]

+1

[g3k0]

+1

[ghost]

+1

[MarkAndrewJohnson]

The benefit of making this a type instead of a loopback option is that if you need to provision for a secondary access method which isn't via loopback then the enum won't validate the input. Obviously not every use case by far but worth keeping in mind.

[AndreasPizsa]

+1

Enums are a common pattern; adding enum support - whether as a type or a constraint - would greatly simplify repeated validity checks on parameters.

[adrien-candiotti]

+1

[yadavji83]

+1

[chadwithuhc]

👍

[joseluisjb1990]

+1

[phil-hawkins]

+1

[hoangtrongphuc]

I have a solution and I'm using it in my project:
In model Game :

color: {
  type: 'string'
}

In game.js file:

module.exports = function(Game) {
  Game.validatesInclusionOf('color', {in: ["hello", "bye"]});
};

[hckhanh]

+100000000

[scippio]

+1

[kjdelisle]

Feature development on loopback@3.x is winding down as a result of our push towards loopback-next. Given the nature of the new framework and its use of TypeScript, support for things like enums will be much easier to implement going forward rather than on this current version.

[terehov]

Does it mean that loopback-next is around the corner and there is a clear migration path?

[kjdelisle]

Loopback-next is going into beta soon and will consist of the most core components of the framework. The intention of the new platform is to focus more of our energy on providing a solid foundation, rather than attempting to build every connector and component for everyone.

Migration
There is a repository implementation called the legacy-juggler-bridge that will allow continued use of your JSON model definitions and the existing loopback-datasource-juggler/connectors.

However, there won't necessarily be a direct upgrade path for your application that transforms your existing logic into a loopback@4.x compatible application. I'd strongly encourage reading the wiki (https://github.com/strongloop/loopback-next/wiki); it's still a work-in-progress but combining it with the loopback-next-example repo should give you insight into loopback-next's many potential workflows and designs.

[kjdelisle]

@terehov Sorry, forgot to add your name to the comment. :P

[randomdev-731]

@kjdelisle Where should I look for enum related model data validations in Loopback 4?

[bajtos]

Let's move the discussion to loopbackio/loopback-next#3033.

[bajtos]

For anybody who lands in this issue: if ENUMs are important to you, then please up-vote loopbackio/loopback-next#3033 by adding a 👍 reaction at the top. Please DO NOT post +1 comments, those are not helpful.