Snippet demonstrating NPM module version tree retrieval.

npm-version-tree.js

'use strict';

const npm = require('npm');
const semver = require('semver');
const graph = {};

function get (moduleName) {
  const silent = true;

  return new Promise((resolve, reject) => {
    npm.load({ loglevel: 'silent', progress: false }, (error) => {
      if (error) {
        reject(error);
      }

      // silencio, por favor
      if (npm && npm.registry && npm.registry.log && npm.registry.log.level) {
        npm.registry.log.level = 'silent';
      }

      npm.commands.info([moduleName], silent, function (error, data) {
        if (error || !data) {
          reject(error || new Error('No data received.'));
        }

        // data is/should be a hash with property names as version number
        for (let version in data) {
          if (!data.hasOwnProperty(version) ||!semver.valid(version)) {
            // look for the next valid property
            continue;
          }

          resolve(data[version]);
          return;
        }

        reject(new Error('Invalid data received.'))
      });
    });
  });
}

async function traverse (moduleName, parent) {
  let module = await get(moduleName),
    keys = module.dependencies ? Object.keys(module.dependencies) : [],
    meta = { version: module.version, parent: parent };

  if (!graph[module.name]) {
    graph[module.name] = [meta];
  }
  else {
    graph[module.name].push(meta);
  }

  return await Promise.all(keys.map(async (dependency) => {
    await traverse(dependency, module.name);
  }));
}

async function execute () {
  await Promise.resolve(traverse('koa', ''));

  let sorted = Object.keys(graph)
                .sort()
                .reduce((result, key) =>
                  (result[key] = graph[key], result),
                  {});

  return sorted;
}

execute().then((result) => { console.log(result); });