Bobby L. Craig

qs

# qs A querystring parsing and stringifying library with some added security. [![Build Status](https://secure.travis-ci.org/hapijs/qs.svg)](http://travis-ci.org/hapijs/qs) Lead Maintainer: [Nathan LaFreniere](https://github.com/nlf) The **qs** module was original created and maintained by [TJ Holowaychuk](https://github.com/visionmedia/node-querystring). ## Usage ```javascript var Qs = require('qs'); var obj = Qs.parse('a=c'); // { a: 'c' } var str = Qs.stringify(obj); // 'a=c' ``` ### Objects **qs** allows you to create nested objects within your query strings, by surrounding the name of sub-keys with square brackets `[]`. For example, the string `'foo[bar]=baz'` converts to: ```javascript { foo: { bar: 'baz' } } ``` You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`: ```javascript { foo: { bar: { baz: 'foobarbaz' } } } ``` By default, when nesting objects **qs** will only parse up to 5 children deep. This means if you attempt to parse a string like `'a[b][c][d][e][f][g][h][i]=j'` your resulting object will be: ```javascript { a: { b: { c: { d: { e: { f: { '[g][h][i]': 'j' } } } } } } } ``` This depth can be overridden by passing a `depth` option to `Qs.parse(string, depth)`: ```javascript Qs.parse('a[b][c][d][e][f][g][h][i]=j', 1); // { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } } ``` The depth limit mitigate abuse when **qs** is used to parse user input, and it is recommended to keep it a reasonably small number. ### Arrays **qs** can also parse arrays using a similar `[]` notation: ```javascript Qs.parse('a[]=b&a[]=c'); // { a: ['b', 'c'] } ``` You may specify an index as well: ```javascript Qs.parse('a[1]=c&a[0]=b'); // { a: ['b', 'c'] } ``` 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 to create an array. When creating arrays with specific indices, **qs** will compact a sparse array to only the existing values preserving their order: ```javascript Qs.parse('a[1]=b&a[15]=c'); // { a: ['b', 'c'] } ``` **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 instead be converted to an object with the index as the key: ```javascript Qs.parse('a[100]=b'); // { a: { '100': 'b' } } ``` If you mix notations, **qs** will merge the two items into an object: ```javascript Qs.parse('a[0]=b&a[b]=c'); // { a: { '0': 'b', b: 'c' } } ``` You can also create arrays of objects: ```javascript Qs.parse('a[][b]=c'); // { a: [{ b: 'c' }] } ```