Function: Configurable()

Configurable<ClassPrototype, DataType>(schema?, fn?): PropertyDecorator<ClassPrototype>

Make the property an option of the object: its value is the option given in the object's declaration ({class: MyComponent, port: 80}) or to getObject(), else the property's initializer, else the default of its schema. The value is validated against the schema, then passed to fn, when the object is created: after its injections, before its init() runs. The declaration replaces an @Inject or @Configurable declaration of the property in a parent class. A module also checks the options of the objects it declares when it initializes, before creating them.

Type Parameters

ClassPrototype

ClassPrototype extends BaseObject

DataType

DataType

Parameters

schema?

Schema<DataType>

The schema validating the value (it may convert it or give its default). Default DTO.Any(): any value, undefined included.

fn?

(this, value) => DataType | Promise<DataType>

A function called with the instance as this and the validated value, returning the value set to the property, of the same type (it may be async). Default: the validated value as it is.

Returns

PropertyDecorator<ClassPrototype>

The property decorator.

Throws

When a module initializes, if an option it declares for the object does not match the schema (all the invalid options are listed).

Throws

When the object is created, if its value does not match the schema (the creation of the object rejects).

Example

import {Application, Component, DTO} from 'lakutata'
import {Configurable} from 'lakutata/decorator/di'

class Server extends Component {
    //80 unless the declaration gives a port
    @Configurable(DTO.Number().integer().min(1).max(65535).optional().default(80))
    protected readonly port!: number

    //The initializer is the default, validated like a configured value
    @Configurable(DTO.String().required())
    protected readonly host: string = '127.0.0.1'

    //The base URL is kept without its trailing slash
    @Configurable(DTO.String().uri().optional().default('http://localhost'), (value: string): string => value.replace(//+$/, ''))
    protected readonly baseURL!: string

    protected async init(): Promise<void> {
        console.log(`Listening on ${this.host}:${this.port} for ${this.baseURL}`)
    }
}

Application.run(() => ({
    id: 'server.app',
    name: 'Server',
    components: {
        server: {class: Server, port: 8080, baseURL: 'https://example.com/'}
    }
}))