@metamask/base-controller/dist/RestrictedMessenger.d.mts

Provides scaffolding for controllers as well a communication system for all controllers

import type { ActionConstraint, ActionHandler, Messenger, EventConstraint, ExtractActionParameters, ExtractActionResponse, ExtractEventHandler, ExtractEventPayload, NamespacedName, NotNamespacedBy, SelectorEventHandler, SelectorFunction } from "./Messenger.mjs";
/**
 * A universal supertype of all `RestrictedMessenger` instances. This type can be assigned to any
 * `RestrictedMessenger` type.
 *
 * @template Namespace - Name of the module this messenger is for. Optionally can be used to
 * narrow this type to a constraint for the messenger of a specific module.
 */
export type RestrictedMessengerConstraint<Namespace extends string = string> = RestrictedMessenger<Namespace, ActionConstraint, EventConstraint, string, string>;
/**
 * A restricted messenger.
 *
 * This acts as a wrapper around the messenger instance that restricts access to actions
 * and events.
 *
 * @template Namespace - The namespace for this messenger. Typically this is the name of the controller or
 * module that this messenger has been created for. The authority to publish events and register
 * actions under this namespace is granted to this restricted messenger instance.
 * @template Action - A type union of all Action types.
 * @template Event - A type union of all Event types.
 * @template AllowedAction - A type union of the 'type' string for any allowed actions.
 * This must not include internal actions that are in the messenger's namespace.
 * @template AllowedEvent - A type union of the 'type' string for any allowed events.
 * This must not include internal events that are in the messenger's namespace.
 */
export declare class RestrictedMessenger<Namespace extends string, Action extends ActionConstraint, Event extends EventConstraint, AllowedAction extends string, AllowedEvent extends string> {
    #private;
    /**
     * Constructs a restricted messenger
     *
     * The provided allowlists grant the ability to call the listed actions and subscribe to the
     * listed events. The "name" provided grants ownership of any actions and events under that
     * namespace. Ownership allows registering actions and publishing events, as well as
     * unregistering actions and clearing event subscriptions.
     *
     * @param options - Options.
     * @param options.messenger - The messenger instance that is being wrapped.
     * @param options.name - The name of the thing this messenger will be handed to (e.g. the
     * controller name). This grants "ownership" of actions and events under this namespace to the
     * restricted messenger returned.
     * @param options.allowedActions - The list of actions that this restricted messenger should be
     * allowed to call.
     * @param options.allowedEvents - The list of events that this restricted messenger should be
     * allowed to subscribe to.
     */
    constructor({ messenger, name, allowedActions, allowedEvents, }: {
        messenger?: Messenger<ActionConstraint, EventConstraint>;
        name: Namespace;
        allowedActions: NotNamespacedBy<Namespace, AllowedAction>[];
        allowedEvents: NotNamespacedBy<Namespace, AllowedEvent>[];
    });
    /**
     * Register an action handler.
     *
     * This will make the registered function available to call via the `call` method.
     *
     * The action type this handler is registered under *must* be in the current namespace.
     *
     * @param action - The action type. This is a unique identifier for this action.
     * @param handler - The action handler. This function gets called when the `call` method is
     * invoked with the given action type.
     * @throws Will throw if an action handler that is not in the current namespace is being registered.
     * @template ActionType - A type union of Action type strings that are namespaced by Namespace.
     */
    registerActionHandler<ActionType extends Action['type'] & NamespacedName<Namespace>>(action: ActionType, handler: ActionHandler<Action, ActionType>): void;
    /**
     * Registers action handlers for a list of methods on a messenger client
     *
     * @param messengerClient - The object that is expected to make use of the messenger.
     * @param methodNames - The names of the methods on the messenger client to register as action
     * handlers.
     * @template MessengerClient - The type expected to make use of the messenger.
     * @template MethodNames - The type union of method names to register as action handlers.
     */
    registerMethodActionHandlers<MessengerClient extends {
        name: string;
    }, MethodNames extends keyof MessengerClient & string>(messengerClient: MessengerClient, methodNames: readonly MethodNames[]): void;
    /**
     * Unregister an action handler.
     *
     * This will prevent this action from being called.
     *
     * The action type being unregistered *must* be in the current namespace.
     *
     * @param action - The action type. This is a unique identifier for this action.
     * @throws Will throw if an action handler that is not in the current namespace is being unregistered.
     * @template ActionType - A type union of Action type strings that are namespaced by Namespace.
     */
    unregisterActionHandler<ActionType extends Action['type'] & NamespacedName<Namespace>>(action: ActionType): void;
    /**
     * Call an action.
     *
     * This function will call the action handler corresponding to the given action type, passing
     * along any parameters given.
     *
     * The action type being called must be on the action allowlist.
     *
     * @param actionType - The action type. This is a unique identifier for this action.
     * @param params - The action parameters. These must match the type of the parameters of the
     * registered action handler.
     * @throws Will throw when no handler has been registered for the given type.
     * @template ActionType - A type union of allowed Action type strings.
     * @returns The action return value.
     */
    call<ActionType extends AllowedAction | (Action['type'] & NamespacedName<Namespace>)>(actionType: ActionType, ...params: ExtractActionParameters<Action, ActionType>): ExtractActionResponse<Action, ActionType>;
    /**
     * Register a function for getting the initial payload for an event.
     *
     * This is used for events that represent a state change, where the payload is the state.
     * Registering a function for getting the payload allows event selectors to have a point of
     * comparison the first time state changes.
     *
     * The event type *must* be in the current namespace
     *
     * @param args - The arguments to this function
     * @param args.eventType - The event type to register a payload for.
     * @param args.getPayload - A function for retrieving the event payload.
     * @template EventType - A type union of Event type strings.
     */
    registerInitialEventPayload<EventType extends Event['type'] & NamespacedName<Namespace>>({ eventType, getPayload, }: {
        eventType: EventType;
        getPayload: () => ExtractEventPayload<Event, EventType>;
    }): void;
    /**
     * Publish an event.
     *
     * Publishes the given payload to all subscribers of the given event type.
     *
     * The event type being published *must* be in the current namespace.
     *
     * @param event - The event type. This is a unique identifier for this event.
     * @param payload - The event payload. The type of the parameters for each event handler must
     * match the type of this payload.
     * @throws Will throw if an event that is not in the current namespace is being published.
     * @template EventType - A type union of Event type strings that are namespaced by Namespace.
     */
    publish<EventType extends Event['type'] & NamespacedName<Namespace>>(event: EventType, ...payload: ExtractEventPayload<Event, EventType>): void;
    /**
     * Subscribe to an event.
     *
     * Registers the given function as an event handler for the given event type.
     *
     * The event type being subscribed to must be on the event allowlist.
     *
     * @param eventType - The event type. This is a unique identifier for this event.
     * @param handler - The event handler. The type of the parameters for this event handler must
     * match the type of the payload for this event type.
     * @throws Will throw if the given event is not an allowed event for this messenger.
     * @template EventType - A type union of Event type strings.
     */
    subscribe<EventType extends AllowedEvent | (Event['type'] & NamespacedName<Namespace>)>(eventType: EventType, handler: ExtractEventHandler<Event, EventType>): void;
    /**
     * Subscribe to an event, with a selector.
     *
     * Registers the given handler function as an event handler for the given
     * event type. When an event is published, its payload is first passed to the
     * selector. The event handler is only called if the selector's return value
     * differs from its last known return value.
     *
     * The event type being subscribed to must be on the event allowlist.
     *
     * @param eventType - The event type. This is a unique identifier for this event.
     * @param handler - The event handler. The type of the parameters for this event
     * handler must match the return type of the selector.
     * @param selector - The selector function used to select relevant data from
     * the event payload. The type of the parameters for this selector must match
     * the type of the payload for this event type.
     * @throws Will throw if the given event is not an allowed event for this messenger.
     * @template EventType - A type union of Event type strings.
     * @template SelectorReturnValue - The selector return value.
     */
    subscribe<EventType extends AllowedEvent | (Event['type'] & NamespacedName<Namespace>), SelectorReturnValue>(eventType: EventType, handler: SelectorEventHandler<SelectorReturnValue>, selector: SelectorFunction<Event, EventType, SelectorReturnValue>): void;
    /**
     * Unsubscribe from an event.
     *
     * Unregisters the given function as an event handler for the given event.
     *
     * The event type being unsubscribed to must be on the event allowlist.
     *
     * @param event - The event type. This is a unique identifier for this event.
     * @param handler - The event handler to unregister.
     * @throws Will throw if the given event is not an allowed event for this messenger.
     * @template EventType - A type union of allowed Event type strings.
     * @template SelectorReturnValue - The selector return value.
     */
    unsubscribe<EventType extends AllowedEvent | (Event['type'] & NamespacedName<Namespace>), SelectorReturnValue = unknown>(event: EventType, handler: ExtractEventHandler<Event, EventType> | SelectorEventHandler<SelectorReturnValue>): void;
    /**
     * Clear subscriptions for a specific event.
     *
     * This will remove all subscribed handlers for this event.
     *
     * The event type being cleared *must* be in the current namespace.
     *
     * @param event - The event type. This is a unique identifier for this event.
     * @throws Will throw if a subscription for an event that is not in the current namespace is being cleared.
     * @template EventType - A type union of Event type strings that are namespaced by Namespace.
     */
    clearEventSubscriptions<EventType extends Event['type'] & NamespacedName<Namespace>>(event: EventType): void;
}
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