# query-string [![Build Status](https://travis-ci.org/sindresorhus/query-string.svg?branch=master)](https://travis-ci.org/sindresorhus/query-string)

> Parse and stringify URL [query strings](https://en.wikipedia.org/wiki/Query_string)


## 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](https://github.com/sindresorhus/query-string/pull/148#issuecomment-399656020), use version 5: `npm install query-string@5`.


## 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`<br>
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`<br>
Default: `'none'`

- `'bracket'`: Parse arrays with bracket representation:

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

- `'index'`: Parse arrays with index representation:

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

- `'none'`: Parse arrays with elements using duplicate keys:

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

##### sort

Type: `Function | boolean`<br>
Default: `true`

Supports both `Function` as a custom sorting function or `false` to disable sorting.

##### parseNumbers

Type: `boolean`<br>
Default: `false`

```js
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`<br>
Default: `false`

```js
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`<br>
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`<br>
Default: `true`

[URL encode](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent) the keys and values.

##### arrayFormat

Type: `string`<br>
Default: `'none'`

- `'bracket'`: Serialize arrays using bracket representation:

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

- `'index'`: Serialize arrays using index representation:

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

- `'none'`: Serialize arrays by using duplicate keys:

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

##### sort

Type: `Function | boolean`

Supports both `Function` as a custom sorting function or `false` to disable sorting.

```js
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
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.

### .extract(string)

Extract a query string from a URL that can be passed into `.parse()`.

### .parseUrl(string, options?)

Extract the URL and the query string as an object.

The `options` are the same as for `.parse()`.

Returns an object with a `url` and `query` property.

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


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

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

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


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