query-string

Parse and stringify URL query strings

^{My open source work is supported by the community}

^{Special thanks to:}

Install

$ npm install query-string

This module targets Node.js 6 or later and the latest version of Chrome, Firefox, and Safari. If you want support for older browsers, or, if your project is using create-react-app v1, use version 5:

npm install [email protected]

Usage

const queryString = require('query-string');

console.log(location.search);
//=> '?foo=bar'
const parsed = queryString.parse(location.search);
console.log(parsed);
//=> {foo: 'bar'}
console.log(location.hash);
//=> '#token=bada55cafe'
const parsedHash = queryString.parse(location.hash);
console.log(parsedHash);
//=> {token: 'bada55cafe'}
parsed.foo = 'unicorn';
parsed.ilike = 'pizza';
const stringified = queryString.stringify(parsed);
//=> 'foo=unicorn&ilike=pizza'
location.search = stringified;
// note that location.search automatically prepends a question mark
console.log(location.search);
//=> '?foo=unicorn&ilike=pizza'

API

.parse(string, options?)

Parse a query string into an object. Leading

?

#

location.search

location.hash

The returned object is created with

Object.create(null)

prototype

options

Type:

object

decode

Type:

boolean

true

Decode the keys and values. URL components are decoded with

decode-uri-component

arrayFormat

Type:

string

'none'

• 'bracket'

  : Parse arrays with bracket representation:

const queryString = require('query-string');

queryString.parse('foo[]=1&foo[]=2&foo[]=3', {arrayFormat: 'bracket'});
//=> {foo: ['1', '2', '3']}

• 'index'

  : Parse arrays with index representation:

const queryString = require('query-string');

queryString.parse('foo[0]=1&foo[1]=2&foo[3]=3', {arrayFormat: 'index'});
//=> {foo: ['1', '2', '3']}

• 'comma'

  : Parse arrays with elements separated by comma:

const queryString = require('query-string');

queryString.parse('foo=1,2,3', {arrayFormat: 'comma'});
//=> {foo: ['1', '2', '3']}

• 'separator'

  : Parse arrays with elements separated by a custom character:

const queryString = require('query-string');

queryString.parse('foo=1|2|3', {arrayFormat: 'separator', arrayFormatSeparator: '|'});
//=> {foo: ['1', '2', '3']}

• 'none'

  : Parse arrays with elements using duplicate keys:

const queryString = require('query-string');

queryString.parse('foo=1&foo=2&foo=3');
//=> {foo: ['1', '2', '3']}

arrayFormatSeparator

Type:

string

','

The character used to separate array elements when using

{arrayFormat: 'separator'}

sort

Type:

Function | boolean

true

Supports both

Function

false

parseNumbers

Type:

boolean

false

const queryString = require('query-string');

queryString.parse('foo=1', {parseNumbers: true});
//=> {foo: 1}

Parse the value as a number type instead of string type if it's a number.

parseBooleans

Type:

boolean

false

const queryString = require('query-string');

queryString.parse('foo=true', {parseBooleans: true});
//=> {foo: true}

Parse the value as a boolean type instead of string type if it's a boolean.

.stringify(object, options?)

Stringify an object into a query string and sorting the keys.

options

Type:

object

strict

Type:

boolean

true

Strictly encode URI components with strict-uri-encode. It uses encodeURIComponent if set to false. You probably don't care about this option.

encode

Type:

boolean

true

URL encode the keys and values.

arrayFormat

Type:

string

'none'

• 'bracket'

  : Serialize arrays using bracket representation:

const queryString = require('query-string');

queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'bracket'});
//=> 'foo[]=1&foo[]=2&foo[]=3'

• 'index'

  : Serialize arrays using index representation:

const queryString = require('query-string');

queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'index'});
//=> 'foo[0]=1&foo[1]=2&foo[2]=3'

• 'comma'

  : Serialize arrays by separating elements with comma:

const queryString = require('query-string');

queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'comma'});
//=> 'foo=1,2,3'

• 'none'

  : Serialize arrays by using duplicate keys:

const queryString = require('query-string');

queryString.stringify({foo: [1, 2, 3]});
//=> 'foo=1&foo=2&foo=3'

arrayFormatSeparator

Type:

string

','

The character used to separate array elements when using

{arrayFormat: 'separator'}

sort

Type:

Function | boolean

Supports both

Function

false

const queryString = require('query-string');

const order = ['c', 'a', 'b'];
queryString.stringify({a: 1, b: 2, c: 3}, {
    sort: (a, b) => order.indexOf(a) - order.indexOf(b)
});
//=> 'c=3&a=1&b=2'

const queryString = require('query-string');

queryString.stringify({b: 1, c: 2, a: 3}, {sort: false});
//=> 'b=1&c=2&a=3'

If omitted, keys are sorted using

Array#sort()

skipNull

Skip keys with

null

Note that keys with

undefined

Type:

boolean

false

const queryString = require('query-string');

queryString.stringify({a: 1, b: undefined, c: null, d: 4}, {
    skipNull: true
});
//=> 'a=1&d=4'

const queryString = require('query-string');

queryString.stringify({a: undefined, b: null}, {
    skipNull: true
});
//=> ''

skipEmptyString

Skip keys with an empty string as the value.

Type:

boolean

false

const queryString = require('query-string');

queryString.stringify({a: 1, b: '', c: '', d: 4}, {
    skipEmptyString: true
});
//=> 'a=1&d=4'

const queryString = require('query-string');

queryString.stringify({a: '', b: ''}, {
    skipEmptyString: true
});
//=> ''

.extract(string)

Extract a query string from a URL that can be passed into

.parse()

Note: This behaviour can be changed with the

skipNull

.parseUrl(string, options?)

Extract the URL and the query string as an object.

Returns an object with a

url

query

If the

parseFragmentIdentifier

true

fragmentIdentifier

const queryString = require('query-string');

queryString.parseUrl('https://foo.bar?foo=bar');
//=> {url: 'https://foo.bar', query: {foo: 'bar'}}
queryString.parseUrl('https://foo.bar?foo=bar#xyz', {parseFragmentIdentifier: true});
//=> {url: 'https://foo.bar', query: {foo: 'bar'}, fragmentIdentifier: 'xyz'}

options

Type:

object

The options are the same as for

.parse()

Extra options are as below.

parseFragmentIdentifier

Parse the fragment identifier from the URL.

Type:

boolean

false

const queryString = require('query-string');

queryString.parseUrl('https://foo.bar?foo=bar#xyz', {parseFragmentIdentifier: true});
//=> {url: 'https://foo.bar', query: {foo: 'bar'}, fragmentIdentifier: 'xyz'}

.stringifyUrl(object, options?)

Stringify an object into a URL with a query string and sorting the keys. The inverse of

.parseUrl()

The

options

.stringify()

Returns a string with the URL and a query string.

Query items in the

query

url

The

fragmentIdentifier

url

queryString.stringifyUrl({url: 'https://foo.bar', query: {foo: 'bar'}});
//=> 'https://foo.bar?foo=bar'

queryString.stringifyUrl({url: 'https://foo.bar?foo=baz', query: {foo: 'bar'}});
//=> 'https://foo.bar?foo=bar'
queryString.stringifyUrl({
    url: 'https://foo.bar',
    query: {
        top: 'foo'
    },
    fragmentIdentifier: 'bar'
});
//=> 'https://foo.bar?top=foo#bar'

object

Type:

object

url

Type:

string

The URL to stringify.

query

Type:

object

Query items to add to the URL.

.pick(url, keys, options?)

.pick(url, filter, options?)

Pick query parameters from a URL.

Returns a string with the new URL.

const queryString = require('query-string');

queryString.pick('https://foo.bar?foo=1&bar=2#hello', ['foo']);
//=> 'https://foo.bar?foo=1#hello'
queryString.pick('https://foo.bar?foo=1&bar=2#hello', (name, value) => value === 2, {parseNumbers: true});
//=> 'https://foo.bar?bar=2#hello'

.exclude(url, keys, options?)

.exclude(url, filter, options?)

Exclude query parameters from a URL.

Returns a string with the new URL.

const queryString = require('query-string');

queryString.exclude('https://foo.bar?foo=1&bar=2#hello', ['foo']);
//=> 'https://foo.bar?bar=2#hello'
queryString.exclude('https://foo.bar?foo=1&bar=2#hello', (name, value) => value === 2, {parseNumbers: true});
//=> 'https://foo.bar?foo=1#hello'

url

Type:

string

The URL containing the query parameters to filter.

keys

Type:

string[]

The names of the query parameters to filter based on the function used.

filter

Type:

(key, value) => boolean

A filter predicate that will be provided the name of each query parameter and its value. The

parseNumbers

parseBooleans

value

options

Type:

object

Parse options and stringify options.

Nesting

This module intentionally doesn't support nesting as it's not spec'd and varies between implementations, which causes a lot of edge cases.

You're much better off just converting the object to a JSON string:

const queryString = require('query-string');

queryString.stringify({
    foo: 'bar',
    nested: JSON.stringify({
        unicorn: 'cake'
    })
});
//=> 'foo=bar&nested=%7B%22unicorn%22%3A%22cake%22%7D'

However, there is support for multiple instances of the same key:

const queryString = require('query-string');

queryString.parse('likes=cake&name=bob&likes=icecream');
//=> {likes: ['cake', 'icecream'], name: 'bob'}
queryString.stringify({color: ['taupe', 'chartreuse'], id: '515'});
//=> 'color=taupe&color=chartreuse&id=515'

Falsy values

Sometimes you want to unset a key, or maybe just make it present without assigning a value to it. Here is how falsy values are stringified:

const queryString = require('query-string');

queryString.stringify({foo: false});
//=> 'foo=false'
queryString.stringify({foo: null});
//=> 'foo'
queryString.stringify({foo: undefined});
//=> ''

query-string for enterprise

Available as part of the Tidelift Subscription.

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