Run this is a node-project to get a list of all repeated dependencies

deps.coffee

fs = require 'fs'
_ = require 'underscore'
{exec} = require 'child_process'

exec 'npm ls', (err, output) ->
  return console.log(err) if err?

  lines = output.split('\n').slice(1, -2)

  packages = lines.map (x) ->
    [all, name, version] = x.match(/\s([^@\s]*)@(.*)$/)
    {name, version}

  groups = _.groupBy(packages, 'name')

  versionGroups = _.pairs(groups).map ([name, data]) ->
    { name, versions: data.map (x) -> x.version }

  sortedVersionGroups = _.sortBy(versionGroups, (x) -> x.versions.length)

  console.log "Installed deps: " + lines.length
  console.log "Packages: " + sortedVersionGroups.length
  console.log sortedVersionGroups