when you're sending/getting from an invalid(wrong case, etc)/non-existant port
when you're attaching/detaching incorrectly
when you don't have an error port
when you use external component libraries, make sure they are using the latest noflo version or you may experience unexpected results
component syntax is invalid, should use lint
when you cannot tell whether why your component isn't getting past its precondition, console.log the buffer helpers so you know what packets are coming in.
when things are getting stuck somewhere along the graph, try flowtrace
calling input.getData when you haven't made sure that input.hasdata
when you send an object to sendDone without specifying the port
calling input.has or input.buffer.* with a port name that is not defined on the components inPorts