The RPi just offers so many more programming language options that it can be confusing… First you need to use Linux to get the thing running, then WiringPi or NodeJS or Python for Blynk, then finding examples can be tricky as the RPI and supporting software seems to change even more rapidly then good old Arduino… yep… tricky.
One way is to take your working non-Blynk NodeJS sketch, merge it with the basic Node connection sketch (you can find some ideas here) to get connected and use a NodeJS friendly blynk.virtualWrite(27, datavalue); // Display Widget on V27 instead of, or along with, whatever console output is used in the original examples.