Querystring library to support Werkzeug's MultiDict features

We built querystring-multidict for consistent typing when reading query strings (e.g. .get() always returns a single string value whereas querystring/qs can return an array/object depending on user input). Additionally, we added .fetch() to make throwing form validation errors easier.

Install the module with: npm install querystring-multidict

// Load in our dependencies and parse a query string
var qsMultiDict = require('querystring-multidict');
var multidict = qsMultiDict.parse('foo=bar&baz=qux&baz=quux&corge');
// Stored as {foo: ['bar'], baz: ['qux', 'quux'], corge: ['']}

// Retrieve either first value or array of values
multidict.get('baz'); // 'qux'
multidict.getArray('baz'); // ['qux', 'quux']

// Supports same parameters as querystring.parse
qsMultiDict.parse('w=%D6%D0%CE%C4&foo=bar', null, null,
  {decodeURIComponent: gbkDecodeURIComponent})
// Stored as {w: ['中文'], foo: ['bar']}

// Retrieve first value or raise an assertion error
var multidict2 = qsMultiDict.parse('foo=bar&baz=qux&baz=quux&corge');
multidict2.fetch('bad-key'); // Raises `MultiDictKeyError` with property `key: 'bad-key'`

querystring-multidict exports the parse function and MultiDictKeyError constructor on exports.

We use a MultiDict data structure based on Werkzeug's implementation.

Retrieve the first value from a key in a MultiDict

• key String - Reference for where to find stored value
• defaultVal String - Optional default value to use when key has no values
  • By default, this will be undefined

Returns:

• val String|undefined - First value stored under key
  • If no value is found, then defaultVal will be returned

Retrieve all values stored under key

• key String - Reference for where to find stored values

Returns:

• val Array - Array of values stored under key
  • If no key is found, then an empty array will be returned

Retrieve the first value from a key in a MultiDict or raise a MultiDictKeyError when key isn't present

• key String - Reference for where to find stored value

Returns:

• val String - First value stored under key

Subclass of an AssertionError with additional key property

• key String - Reference of where key retrieval failed

Parse a query string into a MultiDict

• See Node.js' query string documentation for parameter information
  • https://nodejs.org/api/querystring.html#querystring_querystring_parse_str_sep_eq_options

Returns:

• val MultiDict - MultiDict representation of query string

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint via npm run lint and test via npm test.

Support this project and others by twolfson via gratipay.

As of Jun 06 2016, Todd Wolfson has released this repository and its contents to the public domain.

It has been released under the UNLICENSE.