Instructions for the querystring.parse method in node.js

Method description:

Converts a string into an object. Basically, it turns the string of arguments on the url into an array object. (just look at the example.)

Grammar:

querystring.parse(str, [sep], [eq], [options])

Receiving parameters:

Str                                                                                The string to be converted

Sep                                                                            Set the separator to '&' by default

Eq                                                                                Set the assignment character to '=' by default

[options]   MaxKeys                        The maximum length of an acceptable string, which defaults to 1000

Example:

querystring.parse('foo=bar&baz=qux&baz=quux&corge')

// returns

{ foo: 'bar', baz: ['qux', 'quux'], corge: '' }

Source:

// Parse a key=val string.

QueryString.parse = QueryString.decode = function(qs, sep, eq, options) {

  sep = sep || '&';

  eq = eq || '=';

  var obj = {};

  if (!util.isString(qs) || qs.length === 0) {

    return obj;

  }

  var regexp = /+/g;

  qs = qs.split(sep);

  var maxKeys = 1000;

  if (options && util.isNumber(options.maxKeys)) {

    maxKeys = options.maxKeys;

  }

  var len = qs.length;

  // maxKeys <= 0 means that we should not limit keys count

  if (maxKeys > 0 && len > maxKeys) {

    len = maxKeys;

  }

  for (var i = 0; i < len; ++i) {

    var x = qs[i].replace(regexp, '%20'),

        idx = x.indexOf(eq),

        kstr, vstr, k, v;

    if (idx >= 0) {

      kstr = x.substr(0, idx);

      vstr = x.substr(idx + 1);

    } else {

      kstr = x;

      vstr = '';

    }

    try {

      k = decodeURIComponent(kstr);

      v = decodeURIComponent(vstr);

    } catch (e) {

      k = QueryString.unescape(kstr, true);

      v = QueryString.unescape(vstr, true);

    }

    if (!hasOwnProperty(obj, k)) {

      obj[k] = v;

    } else if (util.isArray(obj[k])) {

      obj[k].push(v);

    } else {

      obj[k] = [obj[k], v];

    }

  }

  return obj;

};