query-string
Version:
Parse and stringify URL query strings
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Markdown
# query-string
> Parse and stringify URL [query strings](https://en.wikipedia.org/wiki/Query_string)
## Install
```sh
npm install query-string
```
> [!WARNING]
> Remember the hyphen! Do not install the deprecated [`querystring`](https://github.com/Gozala/querystring) package!
For browser usage, this package targets the latest version of Chrome, Firefox, and Safari.
> [!TIP]
> Consider using [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) for simple use cases. It's a native browser API that handles basic query string operations.
## Usage
```js
import queryString from '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`.
```js
queryString.parse('?foo=bar');
//=> {foo: 'bar'}
queryString.parse('#token=secret&name=john');
//=> {name: 'john', token: 'secret'}
```
#### options
Type: `object`
##### decode
Type: `boolean`\
Default: `true`
Decode the keys and values. A byte that is not valid UTF-8 becomes the replacement character `U+FFFD`, and the bytes around it are still decoded, like the [`URL` parser](https://developer.mozilla.org/en-US/docs/Web/API/URL) and [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) do. A `%` that is not followed by two hexadecimal digits is not an escape and is kept as it is.
##### arrayFormat
Type: `string`\
Default: `'none'`
- `'bracket'`: Parse arrays with bracket representation:
```js
import queryString from 'query-string';
queryString.parse('foo[]=1&foo[]=2&foo[]=3', {arrayFormat: 'bracket'});
//=> {foo: ['1', '2', '3']}
```
- `'index'`: Parse arrays with index representation:
```js
import queryString from 'query-string';
queryString.parse('foo[0]=1&foo[1]=2&foo[3]=3', {arrayFormat: 'index'});
//=> {foo: ['1', '2', '3']}
```
Entries without an index, such as `foo[]`, are appended after the highest index seen so far. Appending after an index greater than or equal to `Number.MAX_SAFE_INTEGER` is unsupported.
- `'comma'`: Parse arrays with elements separated by comma:
```js
import queryString from 'query-string';
queryString.parse('foo=1,2,3', {arrayFormat: 'comma'});
//=> {foo: ['1', '2', '3']}
queryString.parse('foo=1,2&foo=3', {arrayFormat: 'comma'});
//=> {foo: ['1', '2', '3']}
```
A single value has no separator, so it is a plain value, not an array with one element. Use the [`types`](#types) option to always get an array, or use `'bracket-separator'`, which marks arrays explicitly.
```js
import queryString from 'query-string';
queryString.parse('foo=1', {arrayFormat: 'comma'});
//=> {foo: '1'}
queryString.parse('foo=1', {arrayFormat: 'comma', types: {foo: 'string[]'}});
//=> {foo: ['1']}
```
- `'separator'`: Parse arrays with elements separated by a custom character:
```js
import queryString from '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
import queryString from '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: '|'});
//=> {bar: 'fluffy', baz: ['4'], foo: ['1', '2', '3']}
```
- `'colon-list-separator'`: Parse arrays with parameter names that are explicitly marked with `:list`:
```js
import queryString from '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
import queryString from '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'}`.
Only a literal separator delimits array elements. A percent-encoded separator (for example, `%2C`) is part of the element, which is how [`.stringify()`](#stringifyobject-options) encodes elements that contain the separator. Because of this, `%` and a hexadecimal digit are unsupported, since those also appear inside percent-encoded elements, and so are `&`, `+`, and `#`, since those already have a meaning in a URL: `&` separates parameters, `+` is decoded as a space, and `#` starts the fragment identifier. Those are handled on a best-effort basis, so the result is undefined. Whitespace cannot work at all, since leading and trailing whitespace is ignored when parsing, and a lone surrogate cannot be percent-encoded, so both throw a `TypeError`.
```js
import queryString from 'query-string';
queryString.parse('foo=a%2Cb,c', {arrayFormat: 'comma'});
//=> {foo: ['a,b', 'c']}
queryString.parse('foo[]=a%2Cb,c', {arrayFormat: 'bracket-separator'});
//=> {foo: ['a,b', 'c']}
```
##### sort
Type: `Function | boolean`\
Default: `true`
Supports both `Function` as a custom sorting function or `false` to disable sorting.
If omitted, keys are sorted using `Array#sort()`.
##### parseNumbers
Type: `boolean`\
Default: `false`
```js
import queryString from '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
import queryString from '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.
##### types
Type: `object`\
Default: `{}`
Specifies a schema for parsing query values with explicit type declarations. When defined, the types provided here take precedence over general parsing options such as `parseNumbers`, `parseBooleans`, and `arrayFormat`.
Use this option to explicitly define the type of a specific parameter—particularly useful in cases where the type might otherwise be ambiguous (e.g., phone numbers or IDs).
You can also provide a custom function to transform the value. The function will receive the raw string and should return the desired parsed result. When used with array formats (like `comma`, `separator`, `bracket`, etc.), the function is applied to each array element individually.
Supported Types:
- `'boolean'`: Parse `flagged` as a boolean (overriding the `parseBooleans` option):
```js
import queryString from 'query-string';
queryString.parse('?isAdmin=true&flagged=true&isOkay=0', {
parseBooleans: false,
types: {
flagged: 'boolean',
isOkay: 'boolean',
},
});
//=> {flagged: true, isAdmin: 'true', isOkay: false}
```
Note: The `'boolean'` type also converts `'0'` and `'1'` to booleans, and treats valueless keys (e.g. `?flag`) as `true`.
- `'string'`: Parse `phoneNumber` as a string (overriding the `parseNumbers` option):
```js
import queryString from 'query-string';
queryString.parse('?phoneNumber=%2B380951234567&id=1', {
parseNumbers: true,
types: {
phoneNumber: 'string',
}
});
//=> {id: 1, phoneNumber: '+380951234567'}
```
- `'number'`: Parse `age` as a number (even when `parseNumbers` is false):
```js
import queryString from 'query-string';
queryString.parse('?age=20&id=01234&zipcode=90210', {
types: {
age: 'number',
}
});
//=> {age: 20, id: '01234', zipcode: '90210'}
```
- `'string[]'`: Parse `items` as an array of strings (overriding the `parseNumbers` option):
```js
import queryString from 'query-string';
queryString.parse('?age=20&items=1,2,3', {
arrayFormat: 'comma',
parseNumbers: true,
types: {
items: 'string[]',
}
});
//=> {age: 20, items: ['1', '2', '3']}
```
- `'number[]'`: Parse `items` as an array of numbers (even when `parseNumbers` is false):
```js
import queryString from 'query-string';
queryString.parse('?age=20&items=1,2,3', {
arrayFormat: 'comma',
types: {
items: 'number[]',
}
});
//=> {age: '20', items: [1, 2, 3]}
```
- `'Function'`: Provide a custom function as the parameter type. The parameter's value will equal the function's return value. When used with array formats (like `comma`, `separator`, `bracket`, etc.), the function is applied to each array element individually.
```js
import queryString from 'query-string';
queryString.parse('?age=20&id=01234&zipcode=90210', {
types: {
age: value => value * 2,
}
});
//=> {age: 40, id: '01234', zipcode: '90210'}
// With arrays, the function is applied to each element
queryString.parse('?scores=10,20,30', {
arrayFormat: 'comma',
types: {
scores: value => Number(value) * 2,
}
});
//=> {scores: [20, 40, 60]}
```
NOTE: With `arrayFormat: 'none'`, array types (`string[]`, `number[]`) do not turn a single value into an array. The value stays a string, and `parseNumbers` and `parseBooleans` do not apply to it. A repeated key is still an array, and its items are parsed with the element type.
```js
queryString.parse('ids=001,002,003&foods=apple,orange,mango', {
arrayFormat: 'none',
types: {
ids: 'number[]',
foods: 'string[]',
},
});
//=> {foods: 'apple,orange,mango', ids: '001,002,003'}
```
### .stringify(object, options?)
Stringify an object into a query string and sorting the keys.
**Supported value types:** `string`, `number`, `bigint`, `boolean`, `null`, `undefined`, and arrays of these types. Other types like `Symbol`, functions, or objects (except arrays) will throw an error.
#### options
Type: `object`
##### strict
Type: `boolean`\
Default: `true`
Strictly encode URI components. 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.
A lone surrogate, which cannot be percent-encoded, is replaced with the replacement character U+FFFD, like [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) does.
##### arrayFormat
Type: `string`\
Default: `'none'`
- `'bracket'`: Serialize arrays using bracket representation:
```js
import queryString from 'query-string';
queryString.stringify({foo: [1, 2, 3]}, {arrayFormat: 'bracket'});
//=> 'foo[]=1&foo[]=2&foo[]=3'
```
- `'index'`: Serialize arrays using index representation:
```js
import queryString from '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
import queryString from '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,,', {arrayFormat: 'comma'})` would return `{foo: ['1', '', '']}`.
```
- `'separator'`: Serialize arrays by separating elements with a custom character:
```js
import queryString from '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
import queryString from '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: '|'});
//=> 'bar=fluffy&baz[]=4&foo[]=1|2|3'
```
- `'colon-list-separator'`: Serialize arrays with parameter names that are explicitly marked with `:list`:
```js
import queryString from '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
import queryString from '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'}`.
A separator inside an element is percent-encoded, so [`.parse()`](#parsestring-options) can tell it apart from the separator between elements. With `comma` and `separator`, a plain value that contains the separator is percent-encoded the same way, so it does not turn into an array. Because of this, `%` and a hexadecimal digit are unsupported, since those also appear inside percent-encoded elements, and so are `&`, `+`, and `#`, since those already have a meaning in a URL: `&` separates parameters, `+` is decoded as a space, and `#` starts the fragment identifier. Those are handled on a best-effort basis, so the result is undefined. Whitespace cannot work at all, since leading and trailing whitespace is ignored when parsing, and a lone surrogate cannot be percent-encoded, so both throw a `TypeError`.
##### sort
Type: `Function | boolean`\
Default: `true`
Supports both `Function` as a custom sorting function or `false` to disable sorting.
```js
import queryString from '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
import queryString from '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` as the value.
Note that keys with `undefined` as the value are always skipped.
Type: `boolean`\
Default: `false`
```js
import queryString from 'query-string';
queryString.stringify({a: 1, b: undefined, c: null, d: 4}, {
skipNull: true
});
//=> 'a=1&d=4'
```
```js
import queryString from '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
import queryString from 'query-string';
queryString.stringify({a: 1, b: '', c: '', d: 4}, {
skipEmptyString: true
});
//=> 'a=1&d=4'
```
```js
import queryString from 'query-string';
queryString.stringify({a: '', b: ''}, {
skipEmptyString: true
});
//=> ''
```
##### replacer
A function that transforms key-value pairs before stringification.
Type: `function`\
Default: `undefined`
Similar to the `replacer` parameter of `JSON.stringify()`, this function is called for each key-value pair and can be used to transform values before they are stringified. The function receives the key and value, and should return the transformed value. Returning `undefined` will omit the key-value pair from the resulting query string. The `skipNull` and `skipEmptyString` options apply to the returned value.
This is useful for custom serialization of non-primitive types like `Date`:
```js
import queryString from 'query-string';
queryString.stringify({
date: new Date('2024-01-15T10:30:00Z'),
name: 'John'
}, {
replacer: (key, value) => {
if (value instanceof Date) {
return value.toISOString();
}
return value;
}
});
//=> 'date=2024-01-15T10%3A30%3A00.000Z&name=John'
```
You can also use it to filter out keys:
```js
import queryString from 'query-string';
queryString.stringify({
a: 1,
b: null,
c: 3
}, {
replacer: (key, value) => value === null ? undefined : value
});
//=> 'a=1&c=3'
```
### .extract(string)
Extract a query string from a URL that can be passed into `.parse()`.
```js
queryString.extract('https://foo.bar?foo=bar');
//=> 'foo=bar'
```
### .parseUrl(string, options?)
Extract the URL and the query string as an object. Leading and trailing whitespace is ignored.
Returns an object with a `url` and `query` property.
If the `parseFragmentIdentifier` option is `true`, the object will also contain a `fragmentIdentifier` property.
```js
import queryString from '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
import queryString from '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 query in the `url` property is written back from its plain string values, so `parseNumbers`, `parseBooleans`, and `types` do not rewrite it when the options are shared with [`.parseUrl()`](#parseurlstring-options).
With `encode: false`, an array marker in an existing parameter name is only treated as a marker when it is literal, such as `a[]`, so a percent-encoded marker such as `a%5B%5D` is not overridden by the plain key. The existing parameter is kept as-is, so overriding `a` alongside an existing `a%5B%5D` in the URL writes both `a=2&a%5B%5D=1`.
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. Leading and trailing whitespace is ignored.
##### query
Type: `object`
Query items to add to the URL.
##### fragmentIdentifier
Type: `string`
The fragment identifier to add to the URL, without the leading `#`. An empty string removes the fragment identifier from the URL.
Like the query values, it is a decoded value and is percent-encoded when `encode` is `true`, so [`.parseUrl()`](#parseurlstring-options) reads it back unchanged. `/`, `?`, and `#` are kept as-is, so hash routes like `#/users?id=1` work. When `encode` is `false`, it is written as-is.
```js
import queryString from 'query-string';
queryString.stringifyUrl({url: 'https://foo.bar', fragmentIdentifier: '100%'});
//=> 'https://foo.bar#100%25'
queryString.stringifyUrl({url: 'https://foo.bar', fragmentIdentifier: '/users?id=1'});
//=> 'https://foo.bar#/users?id=1'
```
### .pick(url, keys, options?)
### .pick(url, filter, options?)
Pick query parameters from a URL.
Returns a string with the new URL. The query parameters are sorted, like with [`.stringify()`](#stringifyobject-options). Pass `sort: false` in the options to keep their order. With sorting disabled, integer-index keys come first in ascending numeric order, following JavaScript object enumeration. Repeated keys are grouped together.
```js
import queryString from '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. The query parameters are sorted, like with [`.stringify()`](#stringifyobject-options). Pass `sort: false` in the options to keep their order. With sorting disabled, integer-index keys come first in ascending numeric order, following JavaScript object enumeration. Repeated keys are grouped together.
```js
import queryString from '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. Leading and trailing whitespace is ignored.
#### 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`, and `types` options also affect `value`. They only affect the value passed to the filter. The query parameters are written back to the URL from the plain string values, so a value like `007` is not rewritten as `7`. The query is decoded only when `encode` is `true`, so a value like `a%20b` is not percent-encoded a second time. With `encode: false`, the filter receives the key and value as they are in the URL. The `decode` option is ignored. The stringify options apply to the output, so `skipNull` and `skipEmptyString` also drop a parameter that the filter kept.
#### 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
import queryString from '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
import queryString from '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
import queryString from '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).