Class InMemoryQueryBus

In-memory query bus implementation.

Provides a simple, synchronous query bus for handling queries. Each query type can have only one handler.

Example

const queryBus = new InMemoryQueryBus();

// Register handler
queryBus.register(GetUserQuery, async (query) => {
  return await userRepository.findById(query.userId);
});

// Execute query
const user = await queryBus.execute(new GetUserQuery('123'));

Implements

  • QueryBus

Constructors

constructor

Methods

register execute hasHandler unregister clear

Constructors

constructor

Methods

register

  • register<TQuery extends Query, TResult = unknown>(
        queryType: new (...args: never[]) => TQuery,
        handler:
            | QueryHandler<TQuery, TResult>
            | (query: TQuery) => Promise<TResult>,
    ): void

    Registers a query handler.

    Type Parameters

    • TQuery extends Query

      The query type

    • TResult = unknown

      The result type

    Parameters

    • queryType: new (...args: never[]) => TQuery

      The query class constructor

    • handler: QueryHandler<TQuery, TResult> | (query: TQuery) => Promise<TResult>

      The handler function

    Returns void

    Throws

    If a handler is already registered for this query type

    Example

    queryBus.register(GetUserQuery, async (query) => {
      return await findUser(query.userId);
    });

execute

  • execute<TResult = unknown>(query: Query): Promise<TResult>

    Executes a query through its registered handler.

    Type Parameters

    • TResult = unknown

      The result type

    Parameters

    • query: Query

      The query to execute

    Returns Promise<TResult>

    The result from the query handler

    Throws

    If no handler is registered for this query type

    Example

    const user = await queryBus.execute(new GetUserQuery('123'));

hasHandler

  • hasHandler(queryType: new (...args: never[]) => Query): boolean

    Checks if a handler is registered for a query type.

    Parameters

    • queryType: new (...args: never[]) => Query

      The query class constructor

    Returns boolean

    True if a handler is registered

unregister

  • unregister(queryType: new (...args: never[]) => Query): boolean

    Unregisters a query handler.

    Parameters

    • queryType: new (...args: never[]) => Query

      The query class constructor

    Returns boolean

    True if a handler was unregistered

clear

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