/*
  The original version of this code is taken from Douglas Crockford's json2.js:
  https://github.com/douglascrockford/JSON-js/blob/master/json2.js
  
  I made some modifications to ensure a canonical output.
  */
  
  function f(n) {
      // Format integers to have at least two digits.
      return n < 10 ? '0' + n : n;
  }
  
  var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
      escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
      gap,
      indent,
      meta = {    // table of character substitutions
          '\b': '\\b',
          '\t': '\\t',
          '
  ': '\
  ',
          '\f': '\\f',
          '\r': '\\r',
          '"' : '\\"',
          '\\': '\\\\'
      },
      rep;
  
  
  function quote(string) {
  
  // If the string contains no control characters, no quote characters, and no
  // backslash characters, then we can safely slap some quotes around it.
  // Otherwise we must also replace the offending characters with safe escape
  // sequences.
  
      escapable.lastIndex = 0;
      return escapable.test(string) ? '"' + string.replace(escapable, function (a) {
          var c = meta[a];
          return typeof c === 'string'
              ? c
              : '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
      }) + '"' : '"' + string + '"';
  }
  
  
  function str(key, holder) {
  
  // Produce a string from holder[key].
  
      var i,          // The loop counter.
          k,          // The member key.
          v,          // The member value.
          length,
          mind = gap,
          partial,
          value = holder[key];
  
  // If the value has a toJSON method, call it to obtain a replacement value.
  
      if (value && typeof value === 'object' &&
              typeof value.toJSON === 'function') {
          value = value.toJSON(key);
      }
  
  // If we were called with a replacer function, then call the replacer to
  // obtain a replacement value.
  
      if (typeof rep === 'function') {
          value = rep.call(holder, key, value);
      }
  
  // What happens next depends on the value's type.
  
      switch (typeof value) {
      case 'string':
          return quote(value);
  
      case 'number':
  
  // JSON numbers must be finite. Encode non-finite numbers as null.
  
          return isFinite(value) ? String(value) : 'null';
  
      case 'boolean':
      case 'null':
  
  // If the value is a boolean or null, convert it to a string. Note:
  // typeof null does not produce 'null'. The case is included here in
  // the remote chance that this gets fixed someday.
  
          return String(value);
  
  // If the type is 'object', we might be dealing with an object or an array or
  // null.
  
      case 'object':
  
  // Due to a specification blunder in ECMAScript, typeof null is 'object',
  // so watch out for that case.
  
          if (!value) {
              return 'null';
          }
  
  // Make an array to hold the partial results of stringifying this object value.
  
          gap += indent;
          partial = [];
  
  // Is the value an array?
  
          if (Object.prototype.toString.apply(value) === '[object Array]') {
  
  // The value is an array. Stringify every element. Use null as a placeholder
  // for non-JSON values.
  
              length = value.length;
              for (i = 0; i < length; i += 1) {
                  partial[i] = str(i, value) || 'null';
              }
  
  // Join all of the elements together, separated with commas, and wrap them in
  // brackets.
  
              v = partial.length === 0
                  ? '[]'
                  : gap
                  ? '[
  ' + gap + partial.join(',
  ' + gap) + '
  ' + mind + ']'
                  : '[' + partial.join(',') + ']';
              gap = mind;
              return v;
          }
  
  // If the replacer is an array, use it to select the members to be stringified.
  
          if (rep && typeof rep === 'object') {
              length = rep.length;
              for (i = 0; i < length; i += 1) {
                  if (typeof rep[i] === 'string') {
                      k = rep[i];
                      v = str(k, value);
                      if (v) {
                          partial.push(quote(k) + (gap ? ': ' : ':') + v);
                      }
                  }
              }
          } else {
  
  // Otherwise, iterate through all of the keys in the object.
              var keysSorted = Object.keys(value).sort()
              for (i in keysSorted) {
                  k = keysSorted[i]
                  if (Object.prototype.hasOwnProperty.call(value, k)) {
                      v = str(k, value);
                      if (v) {
                          partial.push(quote(k) + (gap ? ': ' : ':') + v);
                      }
                  }
              }
          }
  
  // Join all of the member texts together, separated with commas,
  // and wrap them in braces.
  
          v = partial.length === 0
              ? '{}'
              : gap
              ? '{
  ' + gap + partial.join(',
  ' + gap) + '
  ' + mind + '}'
              : '{' + partial.join(',') + '}';
          gap = mind;
          return v;
      }
  }
  
  // If the JSON object does not yet have a stringify method, give it one.
  var stringify = function (value, replacer, space) {
  
  // The stringify method takes a value and an optional replacer, and an optional
  // space parameter, and returns a JSON text. The replacer can be a function
  // that can replace values, or an array of strings that will select the keys.
  // A default replacer method can be provided. Use of the space parameter can
  // produce text that is more easily readable.
  
      var i;
      gap = '';
      indent = '';
  
  // If the space parameter is a number, make an indent string containing that
  // many spaces.
  
      if (typeof space === 'number') {
          for (i = 0; i < space; i += 1) {
              indent += ' ';
          }
  
  // If the space parameter is a string, it will be used as the indent string.
  
      } else if (typeof space === 'string') {
          indent = space;
      }
  
  // If there is a replacer, it must be a function or an array.
  // Otherwise, throw an error.
  
      rep = replacer;
      if (replacer && typeof replacer !== 'function' &&
              (typeof replacer !== 'object' ||
              typeof replacer.length !== 'number')) {
          throw new Error('JSON.stringify');
      }
  
  // Make a fake root object containing our value under the key of ''.
  // Return the result of stringifying the value.
  
      return str('', {'': value});
  };
  
  module.exports = stringify