gpahal commented :
There is no limit to connections. When a new client is created using new dgraph.DgraphClient(...DgraphClientStub), a new grpc channel is created for each DgraphClientStub. As long as the server can accept new connections, the client can create new channels.
The node.js grpc client v1.5 added a close method. I’ll add a method DgraphClientStub#close() to close the channel associated with DgraphClientStub. This will take care of cleaning up resources. There are a couple more methods that need to be exposed. They’ll be part of v1.0.1 to be released in a couple of days.