gotu

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 gotu

Using

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

const user = new User()
user.name = "Beth"
user.plan.monthlyCost = 10
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: ["name must be of type string"], plan: { monthlyCost: ["monthlyCost must be of type number"] } }
user.isValid // false

Custom Validation

For custom validation Gotu uses validate.js library under the hood.

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

const User = 
    entity('User', {
        ...
        password: field(String, { 
            presence: true, 
            length: { minimum: 6 },
            message: "must be at least 6 characters"
        })
    })

const user = new User()
user.password = '1234'
user.validate() 
user.errors // { password: ["Password must be at least 6 characters"] }
user.isValid // false

Serialization

fromJSON(value)

Returns a new instance of a entity

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

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

JSON.stringify(entity)

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

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

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)
    })

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()

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 )
• I18n field validation error message
• Entity hidrate (ex: fromJson)
• Entity serialize (ex: toJson)
• Extend / Custom field validation (ex: email, greater than, etc)
• Be able to change validation lib (validate.js)
• 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)

Changelog

1.0.0 (2021-06-23)

Features

• change library to herbs organization (7db11f0)