text: 'use strict';
  
  var utils = require('./utils');
  
  var has = Object.prototype.hasOwnProperty;
  
  var defaults = {
    allowDots: false,
    allowPrototypes: false,
    arrayLimit: 20,
    charset: 'utf-8',
    charsetSentinel: false,
    comma: false,
    decoder: utils.decode,
    delimiter: '&',
    depth: 5,
    ignoreQueryPrefix: false,
    interpretNumericEntities: false,
    parameterLimit: 1000,
    parseArrays: true,
    plainObjects: false,
    strictNullHandling: false
  };
  
  var interpretNumericEntities = function (str) {
    return str.replace(/&#(\d+);/g, function ($0, numberStr) {
      return String.fromCharCode(parseInt(numberStr, 10));
    });
  };
  
  // This is what browsers will submit when the ✓ character occurs in an
  // application/x-www-form-urlencoded body and the encoding of the page containing
  // the form is iso-8859-1, or when the submitted form has an accept-charset
  // attribute of iso-8859-1. Presumably also with other charsets that do not contain
  // the ✓ character, such as us-ascii.
  var isoSentinel = 'utf8=%26%2310003%3B'; // encodeURIComponent('&#10003;')
  
  // These are the percent-encoded utf-8 octets representing a checkmark, indicating that the request actually is utf-8 encoded.
  var charsetSentinel = 'utf8=%E2%9C%93'; // encodeURIComponent('✓')
  
  var parseValues = function parseQueryStringValues(str, options) {
    var obj = {};
    var cleanStr = options.ignoreQueryPrefix ? str.replace(/^\?/, '') : str;
    var limit = options.parameterLimit === Infinity ? undefined : options.parameterLimit;
    var parts = cleanStr.split(options.delimiter, limit);
    var skipIndex = -1; // Keep track of where the utf8 sentinel was found
    var i;
  
    var charset = options.charset;
    if (options.charsetSentinel) {
      for (i = 0; i < parts.length; ++i) {
        if (parts[i].indexOf('utf8=') === 0) {
          if (parts[i] === charsetSentinel) {
            charset = 'utf-8';
          } else if (parts[i] === isoSentinel) {
            charset = 'iso-8859-1';
          }
          skipIndex = i;
          i = parts.length; // The eslint settings do not allow break;
        }
          }
      }
  
      for (i = 0; i < parts.length; ++i) {
        if (i === skipIndex) {
          continue;
        }
        var part = parts[i];
  
        var bracketEqualsPos = part.indexOf(']=');
        var pos = bracketEqualsPos === -1 ? part.indexOf('=') : bracketEqualsPos + 1;
  
        var key, val;
        if (pos === -1) {
          key = options.decoder(part, defaults.decoder, charset);
          val = options.strictNullHandling ? null : '';
        } else {
          key = options.decoder(part.slice(0, pos), defaults.decoder, charset);
          val = options.decoder(part.slice(pos + 1), defaults.decoder, charset);
        }
  
        if (val && options.interpretNumericEntities && charset === 'iso-8859-1') {
          val = interpretNumericEntities(val);
        }
  
        if (val && options.comma && val.indexOf(',') > -1) {
          val = val.split(',');
        }
  
        if (has.call(obj, key)) {
          obj[key] = utils.combine(obj[key], val);
        } else {
          obj[key] = val;
        }
      }
  
    return obj;
  };
  
  var parseObject = function (chain, val, options) {
    var leaf = val;
  
    for (var i = chain.length - 1; i >= 0; --i) {
      var obj;
      var root = chain[i];
  
      if (root === '[]' && options.parseArrays) {
        obj = [].concat(leaf);
      } else {
        obj = options.plainObjects ? Object.create(null) : {};
        var cleanRoot = root.charAt(0) === '[' && root.charAt(root.length - 1) === ']' ? root.slice(1, -1) : root;
        var index = parseInt(cleanRoot, 10);
        if (!options.parseArrays && cleanRoot === '') {
          obj = {0: leaf};
        } else if (
          !isNaN(index)
          && root !== cleanRoot
          && String(index) === cleanRoot
          && index >= 0
          && (options.parseArrays && index <= options.arrayLimit)
        ) {
          obj = [];
                  obj[index] = leaf;
        } else {
          obj[cleanRoot] = leaf;
        }
      }
  
      leaf = obj;
    }
  
    return leaf;
  };
  
  var parseKeys = function parseQueryStringKeys(givenKey, val, options) {
    if (!givenKey) {
      return;
    }
  
    // Transform dot notation to bracket notation
    var key = options.allowDots ? givenKey.replace(/\.([^.[]+)/g, '[$1]') : givenKey;
  
    // The regex chunks
  
    var brackets = /(\[[^[\]]*])/;
    var child = /(\[[^[\]]*])/g;
  
    // Get the parent
  
    var segment = brackets.exec(key);
    var parent = segment ? key.slice(0, segment.index) : key;
  
    // Stash the parent if it exists
  
    var keys = [];
    if (parent) {
      // If we aren't using plain objects, optionally prefix keys that would overwrite object prototype properties
      if (!options.plainObjects && has.call(Object.prototype, parent)) {
        if (!options.allowPrototypes) {
          return;
        }
      }
  
      keys.push(parent);
    }
  
    // Loop through children appending to the array until we hit depth
  
    var i = 0;
    while ((segment = child.exec(key)) !== null && i < options.depth) {
      i += 1;
      if (!options.plainObjects && has.call(Object.prototype, segment[1].slice(1, -1))) {
        if (!options.allowPrototypes) {
          return;
        }
      }
      keys.push(segment[1]);
    }
  
    // If there's a remainder, just add whatever is left
  
    if (segment) {
      keys.push('[' + key.slice(segment.index) + ']');
    }
  
    return parseObject(keys, val, options);
  };
  
  var normalizeParseOptions = function normalizeParseOptions(opts) {
    if (!opts) {
      return defaults;
    }
  
    if (opts.decoder !== null && opts.decoder !== undefined && typeof opts.decoder !== 'function') {
      throw new TypeError('Decoder has to be a function.');
    }
  
    if (typeof opts.charset !== 'undefined' && opts.charset !== 'utf-8' && opts.charset !== 'iso-8859-1') {
      throw new Error('The charset option must be either utf-8, iso-8859-1, or undefined');
    }
    var charset = typeof opts.charset === 'undefined' ? defaults.charset : opts.charset;
  
    return {
      allowDots: typeof opts.allowDots === 'undefined' ? defaults.allowDots : !!opts.allowDots,
      allowPrototypes: typeof opts.allowPrototypes === 'boolean' ? opts.allowPrototypes : defaults.allowPrototypes,
      arrayLimit: typeof opts.arrayLimit === 'number' ? opts.arrayLimit : defaults.arrayLimit,
      charset: charset,
      charsetSentinel: typeof opts.charsetSentinel === 'boolean' ? opts.charsetSentinel : defaults.charsetSentinel,
      comma: typeof opts.comma === 'boolean' ? opts.comma : defaults.comma,
      decoder: typeof opts.decoder === 'function' ? opts.decoder : defaults.decoder,
      delimiter: typeof opts.delimiter === 'string' || utils.isRegExp(opts.delimiter) ? opts.delimiter : defaults.delimiter,
      depth: typeof opts.depth === 'number' ? opts.depth : defaults.depth,
      ignoreQueryPrefix: opts.ignoreQueryPrefix === true,
      interpretNumericEntities: typeof opts.interpretNumericEntities === 'boolean' ? opts.interpretNumericEntities : defaults.interpretNumericEntities,
      parameterLimit: typeof opts.parameterLimit === 'number' ? opts.parameterLimit : defaults.parameterLimit,
      parseArrays: opts.parseArrays !== false,
      plainObjects: typeof opts.plainObjects === 'boolean' ? opts.plainObjects : defaults.plainObjects,
      strictNullHandling: typeof opts.strictNullHandling === 'boolean' ? opts.strictNullHandling : defaults.strictNullHandling
    };
  };
  
  module.exports = function (str, opts) {
    var options = normalizeParseOptions(opts);
  
    if (str === '' || str === null || typeof str === 'undefined') {
      return options.plainObjects ? Object.create(null) : {};
    }
  
    var tempObj = typeof str === 'string' ? parseValues(str, options) : str;
    var obj = options.plainObjects ? Object.create(null) : {};
  
    // Iterate over the keys and setup the new object
  
    var keys = Object.keys(tempObj);
    for (var i = 0; i < keys.length; ++i) {
      var key = keys[i];
      var newObj = parseKeys(key, tempObj[key], options);
      obj = utils.merge(obj, newObj, options);
    }
  
    return utils.compact(obj);
  };
  