nodejs/doc/api/querystring.md

# Query String

    Stability: 2 - Stable

<!--name=querystring-->

This module provides utilities for dealing with query strings.
It provides the following methods:

## querystring.escape
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The escape function used by `querystring.stringify`,
provided so that it could be overridden if necessary.

## querystring.parse(str[, sep][, eq][, options])
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Deserialize a query string to an object.
Optionally override the default separator (`'&'`) and assignment (`'='`)
characters.

Options object may contain `maxKeys` property (equal to 1000 by default), it'll
be used to limit processed keys. Set it to 0 to remove key count limitation.

Options object may contain `decodeURIComponent` property (`querystring.unescape` by default),
it can be used to decode a `non-utf8` encoding string if necessary.

Example:

```js
querystring.parse('foo=bar&baz=qux&baz=quux&corge')
// returns { foo: 'bar', baz: ['qux', 'quux'], corge: '' }

// Suppose gbkDecodeURIComponent function already exists,
// it can decode `gbk` encoding string
querystring.parse('w=%D6%D0%CE%C4&foo=bar', null, null,
  { decodeURIComponent: gbkDecodeURIComponent })
// returns { w: '中文', foo: 'bar' }
```

## querystring.stringify(obj[, sep][, eq][, options])
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Serialize an object to a query string.
Optionally override the default separator (`'&'`) and assignment (`'='`)
characters.

Options object may contain `encodeURIComponent` property (`querystring.escape` by default),
it can be used to encode string with `non-utf8` encoding if necessary.

Example:

```js
querystring.stringify({ foo: 'bar', baz: ['qux', 'quux'], corge: '' })
// returns 'foo=bar&baz=qux&baz=quux&corge='

querystring.stringify({foo: 'bar', baz: 'qux'}, ';', ':')
// returns 'foo:bar;baz:qux'

// Suppose gbkEncodeURIComponent function already exists,
// it can encode string with `gbk` encoding
querystring.stringify({ w: '中文', foo: 'bar' }, null, null,
  { encodeURIComponent: gbkEncodeURIComponent })
// returns 'w=%D6%D0%CE%C4&foo=bar'
```

## querystring.unescape
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The unescape function used by `querystring.parse`,
provided so that it could be overridden if necessary.

It will try to use `decodeURIComponent` in the first place,
but if that fails it falls back to a safer equivalent that
doesn't throw on malformed URLs.