It is possible. The documentation you're looking for is https://learn.microsoft.com/en-us/aspnet/core/signalr/javascript-client?view=aspnetcore-3.1. You can add @microsoft/signalr npm package or use cloudfare cdn. There's sample code in the code.
EDIT: I'm afraid this is not possible it is not possible to run Azure SignalR Service inside a NodeJS server app.