code: function extendedparser (options) {
    var parameterLimit = options.parameterLimit !== undefined
      ? options.parameterLimit
      : 1000
    var parse = parser('qs')
  
    if (isNaN(parameterLimit) || parameterLimit < 1) {
      throw new TypeError('option parameterLimit must be a positive number')
    }
  
    if (isFinite(parameterLimit)) {
      parameterLimit = parameterLimit | 0
    }
  
    return function queryparse (body) {
      var paramCount = parameterCount(body, parameterLimit)
  
      if (paramCount === undefined) {
        debug('too many parameters')
        throw createError(413, 'too many parameters')
      }
  
      var arrayLimit = Math.max(100, paramCount)
  
      debug('parse extended urlencoding')
      return parse(body, {
        allowPrototypes: true,
        arrayLimit: arrayLimit,
        depth: Infinity,
        parameterLimit: parameterLimit
      })
    }
  }
docs: Get the extended query parser.
  
  @param {object} options