# query-string > Parse and stringify URL [query strings](https://en.wikipedia.org/wiki/Query_string)
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## Install ``` $ npm install query-string ``` **Not `npm install querystring`!!!!!** This module targets Node.js 6 or later and the latest version of Chrome, Firefox, and Safari. ## Usage ```js 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 `?` or `#` are ignored, so you can pass `location.search` or `location.hash` directly. The returned object is created with [`Object.create(null)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create) and thus does not have a `prototype`. #### options Type: `object` ##### decode Type: `boolean`\ Default: `true` Decode the keys and values. URL components are decoded with [`decode-uri-component`](https://github.com/SamVerschueren/decode-uri-component). ##### arrayFormat Type: `string`\ Default: `'none'` - `'bracket'`: Parse arrays with bracket representation: ```js 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: ```js 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: ```js 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: ```js const queryString = require('query-string'); queryString.parse('foo=1|2|3', {arrayFormat: 'separator', arrayFormatSeparator: '|'}); //=> {foo: ['1', '2', '3']} ``` - `'bracket-separator'`: Parse arrays (that are explicitly marked with brackets) with elements separated by a custom character: ```js const queryString = require('query-string'); queryString.parse('foo[]', {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> {foo: []} queryString.parse('foo[]=', {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> {foo: ['']} queryString.parse('foo[]=1', {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> {foo: ['1']} queryString.parse('foo[]=1|2|3', {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> {foo: ['1', '2', '3']} queryString.parse('foo[]=1||3|||6', {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> {foo: ['1', '', 3, '', '', '6']} queryString.parse('foo[]=1|2|3&bar=fluffy&baz[]=4', {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> {foo: ['1', '2', '3'], bar: 'fluffy', baz:['4']} ``` - `'colon-list-separator'`: Parse arrays with parameter names that are explicitly marked with `:list`: ```js const queryString = require('query-string'); queryString.parse('foo:list=one&foo:list=two', {arrayFormat: 'colon-list-separator'}); //=> {foo: ['one', 'two']} ``` - `'none'`: Parse arrays with elements using duplicate keys: ```js const queryString = require('query-string'); queryString.parse('foo=1&foo=2&foo=3'); //=> {foo: ['1', '2', '3']} ``` ##### arrayFormatSeparator Type: `string`\ Default: `','` The character used to separate array elements when using `{arrayFormat: 'separator'}`. ##### sort Type: `Function | boolean`\ Default: `true` Supports both `Function` as a custom sorting function or `false` to disable sorting. ##### parseNumbers Type: `boolean`\ Default: `false` ```js 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`\ Default: `false` ```js 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`\ Default: `true` Strictly encode URI components with [strict-uri-encode](https://github.com/kevva/strict-uri-encode). It uses [encodeURIComponent](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent) if set to false. You probably [don't care](https://github.com/sindresorhus/query-string/issues/42) about this option. ##### encode Type: `boolean`\ Default: `true` [URL encode](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent) the keys and values. ##### arrayFormat Type: `string`\ Default: `'none'` - `'bracket'`: Serialize arrays using bracket representation: ```js 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: ```js 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: ```js const queryString = require('query-string'); queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'comma'}); //=> 'foo=1,2,3' queryString.stringify({foo: [1, null, '']}, {arrayFormat: 'comma'}); //=> 'foo=1,,' // Note that typing information for null values is lost // and `.parse('foo=1,,')` would return `{foo: [1, '', '']}`. ``` - `'separator'`: Serialize arrays by separating elements with a custom character: ```js const queryString = require('query-string'); queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'separator', arrayFormatSeparator: '|'}); //=> 'foo=1|2|3' ``` - `'bracket-separator'`: Serialize arrays by explicitly post-fixing array names with brackets and separating elements with a custom character: ```js const queryString = require('query-string'); queryString.stringify({foo: []}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> 'foo[]' queryString.stringify({foo: ['']}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> 'foo[]=' queryString.stringify({foo: [1]}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> 'foo[]=1' queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> 'foo[]=1|2|3' queryString.stringify({foo: [1, '', 3, null, null, 6]}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> 'foo[]=1||3|||6' queryString.stringify({foo: [1, '', 3, null, null, 6]}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|', skipNull: true}); //=> 'foo[]=1||3|6' queryString.stringify({foo: [1, 2, 3], bar: 'fluffy', baz: [4]}, {arrayFormat: 'bracket-separator', arrayFormatSeparator: '|'}); //=> 'foo[]=1|2|3&bar=fluffy&baz[]=4' ``` - `'colon-list-separator'`: Serialize arrays with parameter names that are explicitly marked with `:list`: ```js const queryString = require('query-string'); queryString.stringify({foo: ['one', 'two']}, {arrayFormat: 'colon-list-separator'}); //=> 'foo:list=one&foo:list=two' ``` - `'none'`: Serialize arrays by using duplicate keys: ```js const queryString = require('query-string'); queryString.stringify({foo: [1, 2, 3]}); //=> 'foo=1&foo=2&foo=3' ``` ##### arrayFormatSeparator Type: `string`\ Default: `','` The character used to separate array elements when using `{arrayFormat: 'separator'}`. ##### sort Type: `Function | boolean` Supports both `Function` as a custom sorting function or `false` to disable sorting. ```js 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' ``` ```js 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()`, which means, converting them to strings and comparing strings in Unicode code point order. ##### skipNull Skip keys with `null` as the value. Note that keys with `undefined` as the value are always skipped. Type: `boolean`\ Default: `false` ```js const queryString = require('query-string'); queryString.stringify({a: 1, b: undefined, c: null, d: 4}, { skipNull: true }); //=> 'a=1&d=4' ``` ```js 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`\ Default: `false` ```js const queryString = require('query-string'); queryString.stringify({a: 1, b: '', c: '', d: 4}, { skipEmptyString: true }); //=> 'a=1&d=4' ``` ```js 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` option. ### .parseUrl(string, options?) Extract the URL and the query string as an object. Returns an object with a `url` and `query` property. If the `parseFragmentIdentifier` option is `true`, the object will also contain a `fragmentIdentifier` property. ```js 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`\ Default: `false` ```js 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()`](https://github.com/sindresorhus/query-string#parseurlstring-options) The `options` are the same as for `.stringify()`. Returns a string with the URL and a query string. Query items in the `query` property overrides queries in the `url` property. The `fragmentIdentifier` property overrides the fragment identifier in the `url` property. ```js 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. ```js 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. ```js 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` and `parseBooleans` options also affect `value`. #### options Type: `object` [Parse options](#options) and [stringify options](#options-1). ## 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](https://github.com/visionmedia/node-querystring/issues). You're much better off just converting the object to a JSON string: ```js 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: ```js 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: ```js const queryString = require('query-string'); queryString.stringify({foo: false}); //=> 'foo=false' queryString.stringify({foo: null}); //=> 'foo' queryString.stringify({foo: undefined}); //=> '' ``` ## FAQ ### Why is it parsing `+` as a space? See [this answer](https://github.com/sindresorhus/query-string/issues/305). ## query-string for enterprise Available as part of the Tidelift Subscription. The maintainers of query-string and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-query-string?utm_source=npm-query-string&utm_medium=referral&utm_campaign=enterprise&utm_term=repo)