text: 'use strict';
  
  var Utils = require('./utils');
  
  var internals = {
      delimiter: '&',
      arrayPrefixGenerators: {
          brackets: function (prefix) {
              return prefix + '[]';
          },
          indices: function (prefix, key) {
              return prefix + '[' + key + ']';
          },
          repeat: function (prefix) {
              return prefix;
          }
      },
      strictNullHandling: false,
      skipNulls: false,
      encode: true
  };
  
  internals.stringify = function (object, prefix, generateArrayPrefix, strictNullHandling, skipNulls, encode, filter, sort) {
      var obj = object;
      if (typeof filter === 'function') {
          obj = filter(prefix, obj);
      } else if (Utils.isBuffer(obj)) {
          obj = String(obj);
      } else if (obj instanceof Date) {
          obj = obj.toISOString();
      } else if (obj === null) {
          if (strictNullHandling) {
              return encode ? Utils.encode(prefix) : prefix;
          }
  
          obj = '';
      }
  
      if (typeof obj === 'string' || typeof obj === 'number' || typeof obj === 'boolean') {
          if (encode) {
              return [Utils.encode(prefix) + '=' + Utils.encode(obj)];
          }
          return [prefix + '=' + obj];
      }
  
      var values = [];
  
      if (typeof obj === 'undefined') {
          return values;
      }
  
      var objKeys;
      if (Array.isArray(filter)) {
          objKeys = filter;
      } else {
          var keys = Object.keys(obj);
          objKeys = sort ? keys.sort(sort) : keys;
      }
  
      for (var i = 0; i < objKeys.length; ++i) {
          var key = objKeys[i];
  
          if (skipNulls && obj[key] === null) {
              continue;
          }
  
          if (Array.isArray(obj)) {
              values = values.concat(internals.stringify(obj[key], generateArrayPrefix(prefix, key), generateArrayPrefix, strictNullHandling, skipNulls, encode, filter));
          } else {
              values = values.concat(internals.stringify(obj[key], prefix + '[' + key + ']', generateArrayPrefix, strictNullHandling, skipNulls, encode, filter));
          }
      }
  
      return values;
  };
  
  module.exports = function (object, opts) {
      var obj = object;
      var options = opts || {};
      var delimiter = typeof options.delimiter === 'undefined' ? internals.delimiter : options.delimiter;
      var strictNullHandling = typeof options.strictNullHandling === 'boolean' ? options.strictNullHandling : internals.strictNullHandling;
      var skipNulls = typeof options.skipNulls === 'boolean' ? options.skipNulls : internals.skipNulls;
      var encode = typeof options.encode === 'boolean' ? options.encode : internals.encode;
      var sort = typeof options.sort === 'function' ? options.sort : null;
      var objKeys;
      var filter;
      if (typeof options.filter === 'function') {
          filter = options.filter;
          obj = filter('', obj);
      } else if (Array.isArray(options.filter)) {
          objKeys = filter = options.filter;
      }
  
      var keys = [];
  
      if (typeof obj !== 'object' || obj === null) {
          return '';
      }
  
      var arrayFormat;
      if (options.arrayFormat in internals.arrayPrefixGenerators) {
          arrayFormat = options.arrayFormat;
      } else if ('indices' in options) {
          arrayFormat = options.indices ? 'indices' : 'repeat';
      } else {
          arrayFormat = 'indices';
      }
  
      var generateArrayPrefix = internals.arrayPrefixGenerators[arrayFormat];
  
      if (!objKeys) {
          objKeys = Object.keys(obj);
      }
  
      if (sort) {
          objKeys.sort(sort);
      }
  
      for (var i = 0; i < objKeys.length; ++i) {
          var key = objKeys[i];
  
          if (skipNulls && obj[key] === null) {
              continue;
          }
  
          keys = keys.concat(internals.stringify(obj[key], key, generateArrayPrefix, strictNullHandling, skipNulls, encode, filter, sort));
      }
  
      return keys.join(delimiter);
  };
  