readdir.js
function readScopes (root, kids, cb) {
  var scopes = kids . filter (function (kid) {
    return kid . charAt (0) === '@'
  })

  kids = kids . filter (function (kid) {
    return kid . charAt (0) !== '@'
  })

  debug ('scopes=%j', scopes)

  if (scopes . length === 0)
    dz (cb) (null, kids) // prevent maybe-sync zalgo release

  cb = once (cb)
  var l = scopes . length
  scopes . forEach (function (scope) {
    var scopedir = path . resolve (root, scope)
    debug ('root=%j scope=%j scopedir=%j', root, scope, scopedir)
    fs . readdir (scopedir, then . bind (null, scope))
  })

  function then (scope, er, scopekids) {
    if (er)
      return cb (er)

    // XXX: Not sure how old this node bug is. Maybe superstition?
    scopekids = scopekids . filter (function (scopekid) {
      return !(scopekid === '.' || scopekid === '..' || !scopekid)
    })

    kids . push . apply (kids, scopekids . map (function (scopekid) {
      return scope + '/' + scopekid
    }))

    debug ('scope=%j scopekids=%j kids=%j', scope, scopekids, kids)

    if (--l === 0)
      cb (null, kids)
  }
}
function readScopes (root, kids, cb) {
  var scopes = kids . filter (function (kid) {
    return kid . charAt (0) === '@'
  })

  kids = kids . filter (function (kid) {
    return kid . charAt (0) !== '@'
  })

  debug ('scopes=%j', scopes)

  if (scopes . length === 0)
    dz (cb) (null, kids) // prevent maybe-sync zalgo release

  cb = once (cb)
  var l = scopes . length
  scopes . forEach (function (scope) {
    var scopedir = path . resolve (root, scope)
    debug ('root=%j scope=%j scopedir=%j', root, scope, scopedir)
    fs . readdir (scopedir, then . bind (null, scope))
  })

  function then (scope, er, scopekids) {
    if (er)
      return cb (er)

    // XXX: Not sure how old this node bug is. Maybe superstition?
    scopekids = scopekids . filter (function (scopekid) {
      return !(scopekid === '.' || scopekid === '..' || !scopekid)
    })

    kids . push . apply (kids, scopekids . map (function (scopekid) {
      return scope + '/' + scopekid
    }))

    debug ('scope=%j scopekids=%j kids=%j', scope, scopekids, kids)

    if (--l === 0)
      cb (null, kids)
  }
}
function readScopes ( root , kids , cb ) { var scopes = kids . filter ( function ( kid ) { return kid . charAt ( 0 ) === '@' } ) kids = kids . filter ( function ( kid ) { return kid . charAt ( 0 ) !== '@' } ) debug ( 'scopes=%j' , scopes ) if ( scopes . length === 0 ) dz ( cb ) ( null , kids ) // prevent maybe-sync zalgo release cb = once ( cb ) var l = scopes . length scopes . forEach ( function ( scope ) { var scopedir = path . resolve ( root , scope ) debug ( 'root=%j scope=%j scopedir=%j' , root , scope , scopedir ) fs . readdir ( scopedir , then . bind ( null , scope ) ) } ) function then ( scope , er , scopekids ) { if ( er ) return cb ( er ) // XXX: Not sure how old this node bug is. Maybe superstition? scopekids = scopekids . filter ( function ( scopekid ) { return ! ( scopekid === '.' || scopekid === '..' || ! scopekid ) } ) kids . push . apply ( kids , scopekids . map ( function ( scopekid ) { return scope + '/' + scopekid } ) ) debug ( 'scope=%j scopekids=%j kids=%j' , scope , scopekids , kids ) if ( -- l === 0 ) cb ( null , kids ) } }
Turn [ 'a', '@scope' ] into ['a', '@scope/foo', '@scope/bar']
Turn [ a