Gotu Kola

Gotu Kola helps define your business entities (*)

(*) Entities: they are the first natural place we should aim to place business logic in domain-driven applications.

Installing

$ npm install @herbsjs/gotu

Using

const { entity, field } = require('@herbsjs/gotu')

const Feature =
        entity('Feature', {
            name: field(String),
            hasAccess: field(Boolean)
        })

const Plan =
    entity('Plan', {
        name: field(String),
        monthlyCost: field(Number)
    })

const User =
    entity('User', {
        name: field(String),
        lastAccess: field(Date),
        accessCount: field(Number),
        features: field([Feature]),
        plan: field(Plan),
    })

const user = new User()
user.name = "Beth"
user.plan.monthlyCost = 10
user.features = [
    new Feature(),
    new Feature(),
    new Feature()
]
user.validate()

Validation

A value of an field can be validated against the field type or its custom validation.

Type Validation

const Plan =
    entity('Plan', {
        ...
        monthlyCost: field(Number),
    })

const User =
    entity('User', {
        name: field(String),
        plan: field(Plan)
    })

const user = new User()
user.name = 42
user.plan.monthlyCost = true
user.validate()
user.errors // { name: [ wrongType: 'String' ], plan: { monthlyCost: [ wrongType: 'Number' ] } }
user.isValid() // false

You can also simplify you validation method using isValid() method that execute validate implicit for you entity and return true/false in a single execution and also you can check the errors.

const Plan =
    entity('Plan', {
        ...
        monthlyCost: field(Number),
    })

const plan = new Plan()
plan.plan.monthlyCost = true
plan.isValid() // false
plan.errors // { monthlyCost: [ wrongType: 'Number' ] }

You can ignore id field validation using isValid({exceptIDs: true}). Example: Imagine that your id should not be null, but sometimes, in an insertion case, the ID only exists after an insertion in the database, so you can validate the hole entity, except the id field.

const Plan =
    entity('Plan', {
        ...
        myId: id(Number),
        monthlyCost: field(Number),
    })

const plan = new Plan()
plan.plan.myId = '123'
plan.plan.monthlyCost = 500
plan.isValid({exceptIDs: true}) // true

plan.isValid() // false
plan.errors // { myId: [ wrongType: 'Number' ] }

Custom Validation

For custom validation Gotu uses Herbs JS Suma library under the hood. It has no message defined, only error codes.

Use { validation: ... } to specify a valid Suma validation (sorry) on the field definition.

const User =
    entity('User', {
        ...
        password: field(String, validation: {
            presence: true,
            length: { minimum: 6 }
        }),
        cardNumber: field(String, validation: {
          custom: { invalidCardNumber: (value) => value.length === 16 }
        })
    })

const user = new User()
user.password = '1234'
user.cardNumber = '1234456'
user.validate()
user.errors // [{ password: [ { isTooShort: 6 } ] , { "invalidCardNumber": true }]
user.isValid // false

Serialization

fromJSON(value)

Returns a new instance of a entity

const User =
    entity('User', {
        name: field(String)
    })

// from object
const user = User.fromJSON({ name: 'Beth'})
// or string
const user = User.fromJSON(`{ "name": "Beth"}`)

By default fromJSON serializes only keys that have been defined in the entity. If you want to add other keys during serialization, use .fromJSON(data, { allowExtraKeys: true }).

By default, fromJSON default field values will be applied for keys not present in value.

JSON.stringify(entity)

To serialize an entity to JSON string use JSON.stringify or entity.toJSON function.

const json = JSON.stringify(user) // { "name": "Beth" }

By default toJSON serializes only keys that have been defined in the entity. If you want to add other keys during serialization, use entity.toJSON({ allowExtraKeys: true }).

Field definition

A entity field type has a name, type, default value, validation and more.

Scalar types

A field in an entity can be of basic types, the same as those used by JavaScript:

Number: double-precision 64-bit binary format IEEE 754 value

String: a UTF‐16 character sequence

Boolean: true or false

Date: represents a single moment in time in a platform-independent format.

const User =
    entity('User', {
        name: field(String),
        lastAccess: field(Date),
        accessCount: field(Number),
        hasAccess: field(Boolean)
    })

Entity type

For complex types, with deep relationship between entities, a field can be of entity type:

const Plan =
    entity('Plan', {
        ...
        monthlyCost: field(Number),
    })

const User =
    entity('User', {
        ...
        plan: field(Plan)
    })

List of Entity type

For complex types, with deep relationship between entities, a field can contain a list of entity type:

const Plan =
    entity('Plan', {
        ...
        monthlyCost: field(Number),
    })

const User =
    entity('User', {
        ...
        plan: field([Plan])
    })

ID Fields

It is possible to declare a field as an ID. This metadata will be used by glues to enrich the infrastructure interfaces (Database, REST, GraphQL, etc).

We can do it in two ways:

// The explicit way
const User =
    entity('User', {
        id: field(Number, { isId: true }),
        ...
    })

// The short way
const User =
    entity('User', {
        id: id(Number),
        ...
    })

You can check if a field isId accessing the options of the field, like this:

const user = new User()

//should be equals ```true```
user.__proto__.meta.schema.id.options.isId

Default value

It is possible to define a default value when an entity instance is initiate.

const User =
    entity('User', {
        ...
        hasAccess: field(Boolean, { default: false })
    })


const user = new User()
user.hasAccess // false

If the default value is a function it will call the function and return the value as default value:

const User =
    entity('User', {
        ...
        hasAccess: field(Boolean, { default: () => false })
    })


const user = new User()
user.hasAccess // false

For scalar types a default value is assumed if a default value is not given:

Type	Default Value
Number	0
String	""
Boolean	false
Date	null

For entity types the default value is a new instance of that type. It is possible to use null as default:

const User =
    entity('User', {
        ...
        plan: field(Plan, { default: null })
    })

const user = new User()
user.plan // null

Method definition

A method can be defined to create custom behaviour in an entity:

const User =
    entity('User', {
        ...
        role: field(String),
        hasAccess() { return this.role === "admin" },
    })

const user = new User()
const access = user.hasAccess()

Instance Type Check - Entity.parentOf

Check if a instance is the same type from its parent entity class (similar to instanceOf)

        const AnEntity = entity('A entity', {})
        const AnSecondEntity = entity('A second entity', {})

        const instance1 = new AnEntity()
        const instance2 = new AnSecondEntity()

        AnEntity.parentOf(instance1) // true
        AnEntity.parentOf(instance2) // false

Entity Type Check - entity.isEntity

Check if an object is a Gotu Entity class

        const AnEntity = entity('A entity', {})

        const instance1 = new AnEntity()

        entity.isEntity(AnEntity) // true
        entity.isEntity(Object) // false

TODO

• Field basic JS type definition and validation (ex: "name": String)
• Field entity type definition and validation (ex: "user": User)
• Field enum type definition and validation (ex: "paymentType": ['CC', 'Check'])
• Field list type definition and validation (ex: "users": [User])
• Entity custom methods (ex: payment.calculate())
• Default values
• Entity (complex) validation (ex: payment.validate() )
• Field validation error message (ex: payment.errors )
• Field validation error code (ex: payment.errors )
• Entity hidrate (ex: fromJson)
• Entity serialize (ex: toJson)
• Extend / Custom field validation (ex: email, greater than, etc)
• Valitation contexts (ex: Payment validation for [1] credit card or [2] check)
• Conditional Validation (ex: if email is present, emailConfirmation must be present)
• Entities Inheritance (schema and validations inheritance)

Contribute

Come with us to make an awesome Gotu.

Now, if you do not have technical knowledge and also have intend to help us, do not feel shy, click here to open an issue and collaborate their ideas, the contribution may be a criticism or a compliment (why not?)

If you would like to help contribute to this repository, please see CONTRIBUTING

The Herb

Gotu Kola has been used historically to relieve congestion from upper respiratory infections and colds and for wound healing. It is very popular for treating varicose veins and memory loss.

https://www.herbslist.net/

https://en.wikipedia.org/wiki/Centella_asiatica

License

Gotu is released under the MIT license.