Your can find the repository of the example decoder on Github.
decoder_ttn.js is required to be used instead of
The Decoder function in the decoder.js is a self contained function, that takes a Buffer as it's input and returns an Object containing the decoded payload.
Make sure you also have all dev-dependencies installed, then run npm test.
Execute node test.js
node test.js 17ecfb8b010b1100001d804000430031520f9f680032520b45090034520f9722 to see the parsed result commandline.