import { ResultStreamObserver } from "https://deno.land/x/neo4j_lite_client@4.4.6/bolt-connection/bolt/index.js";
Handles a RUN/PULL_ALL, or RUN/DISCARD_ALL requests, maps the responses in a way that a user-provided observer can see these as a clean Stream of records. This class will queue up incoming messages until a user-provided observer for the incoming stream is registered. Thus, we keep fields around for tracking head/records/tail. These are only used if there is no observer registered.
Methods
Cancel pending record stream
Mark this observer as if it has completed with no metadata.
Will be called on errors. If user-provided observer is present, pass the error to it's onError method, otherwise set instance variable _error.
Will be called on every record that comes in and transform a raw record to a Object. If user-provided observer is present, pass transformed record to it's onNext method, otherwise, push to record que.
Stream observer defaults to handling responses for two messages: RUN + PULL_ALL or RUN + DISCARD_ALL. Response for RUN initializes query keys. Response for PULL_ALL / DISCARD_ALL exposes the result stream.
However, some operations can be represented as a single message which receives full metadata in a single response.
For example, operations to begin, commit and rollback an explicit transaction use two messages in Bolt V1 but a single message in Bolt V3.
Messages are RUN "BEGIN" {} + PULL_ALL in Bolt V1 and BEGIN in Bolt V3.
This function prepares the observer to only handle a single response message.
Subscribe to events with provided observer.