const parsedData = parseAccountData(rootNode, bytes); // For parsing accounts. OR
const parsedData = parseInstructionData(rootNode, bytes); // For parsing instructions.

if(!parsedData) throw new Error("Could not identify account/instruction on the program");

parsedData.data // the JSON-compatible decoded data.
parsedData.path // the NodePath identified by the bytes on the program.

const node = getLastNodeFromPath(parsedData.path)
//    ^ The account/instruction node used to decode the bytes.