code: function _identifiers (options) {
    var query = {}
  
    for (var prop in options.hash) {
      if (/^-/.test(prop)) {
        query[prop.replace(/^-/, '!')] = options.hash[prop]
      } else if (/^_/.test(prop)) {
        query[prop.replace(/^_/, '')] = new RegExp(options.hash[prop])
      } else {
        query[prop] = options.hash[prop]
      }
    }
    return arrayify(options.data.root).filter(where(query))
  }
docs: Returns an array of identifiers matching the query
  @returns {array}
  @static