npm install node-red-module-parser

const nodeRedModule = require('node-red-module-parser')

let moduleInfo = nodeRedModule.examinModule('/path/to/module/dir')
let moduleInto = nodeRedModule.examinTar('/path/to/tar/file','/path/to/temp/dir/location')

Where the module dir is the directory that holds the package.json file for the node, or the tgz file is the output of npm pack or the packaged module downloaded from a npm repository.

moduleInfo is an augmented package.json with details of the node types, default values and icon information.s