index.js

#! /usr/bin/env node

window = {}
document = {}

var fs = require('fs')
var path = require('path')
var isDepject = require('depject/is')

function Filter (stat) {
  if(stat.name === 'node_modules') return
  if(/^\./.test(stat.name)) return
  if(stat.isDirectory()) return true
  if(/\.js$/.test(stat.name)) return true
}

function Map (stat) {
  try {
    var m = require(stat.path)
    if(isDepject(m)) {
      if('string' === typeof m.gives) {
        var o = {}
        o[m.gives] = true
        return {gives: o, needs: m.needs}
      }
      return m
    }
  } catch (err) {
    return err.message
  }
}

function walk (dir, filter, map) {
  filter = filter || Filter
  map = map || Map
  var o = {}
  fs.readdirSync(dir)
  .forEach(function (file) {
    var filename = path.join(dir, file)
    var stat = fs.statSync(filename)
    stat.name = file
    stat.path = filename

    if(!filter(stat)) return
    if(stat.isDirectory())
      o[file] = walk(filename, filter, map)
    else
      o[file] = map(stat)
  })
  return o
}

module.exports = function (dirs) {
  if('string' == typeof dirs) dirs = [dirs]

  var files = {}
  dirs.forEach(function (dir) {
    walk(
      path.resolve(process.cwd(), dir),
      Filter,
      function (e) {
        files[e.path] = Map(e)
      }
    )
  })
  var _files = files; files = {}
  for(var k in _files)
    files[path.relative(process.cwd(), k)] = _files[k]

  var N = require('libnested')

  return N.map(files, function (value, path) {
    var last = path[path.length - 1]
    if(path[1] == 'gives') {
      if('string' === typeof value) {
        path.push(value)
      }
      var needed = []
      for(var k in files) {
        var m = files[k]
        if(m && m.needs && N.get(m.needs, path.slice(2)))
          needed.push(k)
      }
      return needed
    }
    else if(path[1] == 'needs') {
      var given = []
      for(var k in files) {
        var m = files[k]
        if(m && m.gives && path && N.get(m.gives, path.slice(2)))
          given.push(k)
      }
      return given
    }
  })
}

if(!module.parent) {
  var dirs = process.argv.slice(2)
  if(!dirs.length) dirs = [process.cwd()]

  console.log(JSON.stringify(module.exports(dirs), null, 2))
  process.exit(0)
}