3 A querystring parsing and stringifying library with some added security.
5 [![Build Status](https://secure.travis-ci.org/hapijs/qs.svg)](http://travis-ci.org/hapijs/qs)
7 Lead Maintainer: [Nathan LaFreniere](https://github.com/nlf)
9 The **qs** module was originally created and maintained by [TJ Holowaychuk](https://github.com/visionmedia/node-querystring).
14 var Qs = require('qs');
16 var obj = Qs.parse('a=c'); // { a: 'c' }
17 var str = Qs.stringify(obj); // 'a=c'
23 Qs.parse(string, [options]);
26 **qs** allows you to create nested objects within your query strings, by surrounding the name of sub-keys with square brackets `[]`.
27 For example, the string `'foo[bar]=baz'` converts to:
37 URI encoded strings work too:
40 Qs.parse('a%5Bb%5D=c');
44 You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`:
56 By default, when nesting objects **qs** will only parse up to 5 children deep. This means if you attempt to parse a string like
57 `'a[b][c][d][e][f][g][h][i]=j'` your resulting object will be:
77 This depth can be overridden by passing a `depth` option to `Qs.parse(string, [options])`:
80 Qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
81 // { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } }
84 The depth limit helps mitigate abuse when **qs** is used to parse user input, and it is recommended to keep it a reasonably small number.
86 For similar reasons, by default **qs** will only parse up to 1000 parameters. This can be overridden by passing a `parameterLimit` option:
89 Qs.parse('a=b&c=d', { parameterLimit: 1 });
93 An optional delimiter can also be passed:
96 Qs.parse('a=b;c=d', { delimiter: ';' });
100 Delimiters can be a regular expression too:
103 Qs.parse('a=b;c=d,e=f', { delimiter: /[;,]/ });
104 // { a: 'b', c: 'd', e: 'f' }
109 **qs** can also parse arrays using a similar `[]` notation:
112 Qs.parse('a[]=b&a[]=c');
116 You may specify an index as well:
119 Qs.parse('a[1]=c&a[0]=b');
123 Note that the only difference between an index in an array and a key in an object is that the value between the brackets must be a number
124 to create an array. When creating arrays with specific indices, **qs** will compact a sparse array to only the existing values preserving
128 Qs.parse('a[1]=b&a[15]=c');
132 Note that an empty string is also a value, and will be preserved:
135 Qs.parse('a[]=&a[]=b');
137 Qs.parse('a[0]=b&a[1]=&a[2]=c');
138 // { a: ['b', '', 'c'] }
141 **qs** will also limit specifying indices in an array to a maximum index of `20`. Any array members with an index of greater than `20` will
142 instead be converted to an object with the index as the key:
145 Qs.parse('a[100]=b');
146 // { a: { '100': 'b' } }
149 This limit can be overridden by passing an `arrayLimit` option:
152 Qs.parse('a[1]=b', { arrayLimit: 0 });
153 // { a: { '1': 'b' } }
156 To disable array parsing entirely, set `arrayLimit` to `-1`.
158 If you mix notations, **qs** will merge the two items into an object:
161 Qs.parse('a[0]=b&a[b]=c');
162 // { a: { '0': 'b', b: 'c' } }
165 You can also create arrays of objects:
168 Qs.parse('a[][b]=c');
169 // { a: [{ b: 'c' }] }
175 Qs.stringify(object, [options]);
178 When stringifying, **qs** always URI encodes output. Objects are stringified as you would expect:
181 Qs.stringify({ a: 'b' });
183 Qs.stringify({ a: { b: 'c' } });
187 Examples beyond this point will be shown as though the output is not URI encoded for clarity. Please note that the return values in these cases *will* be URI encoded during real usage.
189 When arrays are stringified, by default they are given explicit indices:
192 Qs.stringify({ a: ['b', 'c', 'd'] });
193 // 'a[0]=b&a[1]=c&a[2]=d'
196 You may override this by setting the `indices` option to `false`:
199 Qs.stringify({ a: ['b', 'c', 'd'] }, { indices: false });
203 Empty strings and null values will omit the value, but the equals sign (=) remains in place:
206 Qs.stringify({ a: '' });
210 Properties that are set to `undefined` will be omitted entirely:
213 Qs.stringify({ a: null, b: undefined });
217 The delimiter may be overridden with stringify as well:
220 Qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' });