Interface IPlugin<T, U>

A user-defined application plugin.

interface IPlugin<T, U> {
    activate: ((app, ...args) => U | Promise<U>);
    autoStart?: boolean | "defer";
    deactivate?: null | ((app, ...args) => void | Promise<void>);
    description?: string;
    id: string;
    optional?: Token<any>[];
    provides?: null | Token<U>;
    requires?: Token<any>[];
}

Type Parameters

  • T

    The type for the application.

  • U

    The service type, if the plugin provides one.

    Notes

    Plugins are the foundation for building an extensible application.

    Plugins consume and provide "services", which are nothing more than concrete implementations of interfaces and/or abstract types.

    Unlike regular imports and exports, which tie the service consumer to a particular implementation of the service, plugins decouple the service producer from the service consumer, allowing an application to be easily customized by third parties in a type-safe fashion.

Properties

activate autoStart? deactivate? description? id optional? provides? requires?

Properties

activate

activate: ((app, ...args) => U | Promise<U>)

A function invoked to activate the plugin.

Type declaration

Returns

The provided service, or a promise to the service.

Notes

This function will be called whenever the plugin is manually activated, or when another plugin being activated requires the service it provides.

This function will not be called unless all of its required services can be fulfilled.

Optional autoStart

autoStart?: boolean | "defer"

Whether the plugin should be activated on application start or waiting for being required. If the value is 'defer' then the plugin should be activated only after the application is started.

Notes

The default is false.

Optional deactivate

deactivate?: null | ((app, ...args) => void | Promise<void>)

A function invoked to deactivate the plugin.

Type declaration

    • (app, ...args): void | Promise<void>

    • Parameters

      • app: T
      • Rest ...args: any[]

      Returns void | Promise<void>

Param: app

The application PluginRegistry.application .

Param: args

The services specified by the requires property.

Optional description

description?: string

Plugin description.

Notes

This can be used to provide user documentation on the feature brought by a plugin.

id

id: string

The human readable ID of the plugin.

Notes

This must be unique within an application.

Optional optional

optional?: Token<any>[]

The types of optional services for the plugin, if any.

Notes

These tokens correspond to the services that can be used by the plugin if available, but are not necessarily required.

The optional services will be passed to the activate() function following all required services. If an optional service cannot be resolved, null will be passed in its place.

Optional provides

provides?: null | Token<U>

The type of service provided by the plugin, if any.

Notes

This token corresponds to the service exported by the plugin.

When the plugin is activated, the return value of activate() is used as the concrete instance of the type.

Optional requires

requires?: Token<any>[]

The types of required services for the plugin, if any.

Notes

These tokens correspond to the services that are required by the plugin for correct operation.

When the plugin is activated, a concrete instance of each type will be passed to the activate() function, in the order they are specified in the requires array.

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