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Node.js v8.0.0 Documentation
Table of Contents
Query String#
Stability: 2 - Stable
The querystring
module provides utilities for parsing and formatting URL
query strings. It can be accessed using:
const querystring = require('querystring');
querystring.escape(str)#
str
<string>
The querystring.escape()
method performs URL percent-encoding on the given
str
in a manner that is optimized for the specific requirements of URL
query strings.
The querystring.escape()
method is used by querystring.stringify()
and is
generally not expected to be used directly. It is exported primarily to allow
application code to provide a replacement percent-encoding implementation if
necessary by assigning querystring.escape
to an alternative function.
querystring.parse(str[, sep[, eq[, options]]])#
str
<string> The URL query string to parsesep
<string> The substring used to delimit key and value pairs in the query string. Defaults to'&'
.eq
<string>. The substring used to delimit keys and values in the query string. Defaults to'='
.options
<Object>decodeURIComponent
<Function> The function to use when decoding percent-encoded characters in the query string. Defaults toquerystring.unescape()
.maxKeys
<number> Specifies the maximum number of keys to parse. Defaults to1000
. Specify0
to remove key counting limitations.
The querystring.parse()
method parses a URL query string (str
) into a
collection of key and value pairs.
For example, the query string 'foo=bar&abc=xyz&abc=123'
is parsed into:
{
foo: 'bar',
abc: ['xyz', '123']
}
Note: The object returned by the querystring.parse()
method does not
prototypically inherit from the JavaScript Object
. This means that typical
Object
methods such as obj.toString()
, obj.hasOwnProperty()
, and others
are not defined and will not work.
By default, percent-encoded characters within the query string will be assumed
to use UTF-8 encoding. If an alternative character encoding is used, then an
alternative decodeURIComponent
option will need to be specified as illustrated
in the following example:
// Assuming gbkDecodeURIComponent function already exists...
querystring.parse('w=%D6%D0%CE%C4&foo=bar', null, null,
{ decodeURIComponent: gbkDecodeURIComponent });
querystring.stringify(obj[, sep[, eq[, options]]])#
obj
<Object> The object to serialize into a URL query stringsep
<string> The substring used to delimit key and value pairs in the query string. Defaults to'&'
.eq
<string>. The substring used to delimit keys and values in the query string. Defaults to'='
.options
encodeURIComponent
<Function> The function to use when converting URL-unsafe characters to percent-encoding in the query string. Defaults toquerystring.escape()
.
The querystring.stringify()
method produces a URL query string from a
given obj
by iterating through the object's "own properties".
It serializes the following types of values passed in obj
:
<string> | <number> | <boolean> | <string[]> | <number[]> | <boolean[]>
Any other input values will be coerced to empty strings.
For example:
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'
By default, characters requiring percent-encoding within the query string will
be encoded as UTF-8. If an alternative encoding is required, then an alternative
encodeURIComponent
option will need to be specified as illustrated in the
following example:
// Assuming gbkEncodeURIComponent function already exists,
querystring.stringify({ w: '中文', foo: 'bar' }, null, null,
{ encodeURIComponent: gbkEncodeURIComponent });
querystring.unescape(str)#
str
<string>
The querystring.unescape()
method performs decoding of URL percent-encoded
characters on the given str
.
The querystring.unescape()
method is used by querystring.parse()
and is
generally not expected to be used directly. It is exported primarily to allow
application code to provide a replacement decoding implementation if
necessary by assigning querystring.unescape
to an alternative function.
By default, the querystring.unescape()
method will attempt to use the
JavaScript built-in decodeURIComponent()
method to decode. If that fails,
a safer equivalent that does not throw on malformed URLs will be used.