Add support for options.qs

README.md

@@ -60,6 +60,7 @@ type XhrOptions = String | {
     withCredentials: Boolean?,
     responseType: String?,
     beforeSend: Function?
+    qs: Any?
 }
 xhr := (XhrOptions, Callback<Response>) => Request
 ```
@@ -193,6 +194,17 @@ A function being called right before the `send` method of the `XMLHttpRequest` o
 
 Pass an `XMLHttpRequest` object (or something that acts like one) to use instead of constructing a new one using the `XMLHttpRequest` or `XDomainRequest` constructors. Useful for testing.
 
+### `options.qs`
+
+A value to be transformed into a query string. This library does not provide
+a parser for `options.qs` out of the box: you must define it yourself as
+`xhr.queryStringStringify`.
+
+If `options.qs` is defined, and `xhr.queryStringStringify` is not, then an
+Error will be thrown.
+
+For more, see [Query string support](#query-string-support).
+
 ## FAQ
 
 - Why is my server's JSON response not parsed? I returned the right content-type.
@@ -216,6 +228,8 @@ xhr({
   }
 })
 ```
+- How can I support query strings?
+  - See [Query string support](#query-string-support)
 
 ## Mocking Requests
 You can override the constructor used to create new requests for testing. When you're making a new request:
@@ -231,6 +245,31 @@ xhr.XMLHttpRequest = MockXMLHttpRequest
 xhr.XDomainRequest = MockXDomainRequest
 ```
 
+## Query string support
+There are many ways to stringify query parameters; consequently, `xhr` makes no
+assumptions about how to handle them, and does not support the `qs` option out
+of the box.
+
+To support the `qs` option, you must define an `xhr.queryStringStringify`
+function. This function accepts the value of `options.qs` as its first argument,
+and returns a string that is appended to the URL.
+
+You do not need to include a leading "?" in the value that you return from
+`xhr.queryStringStringify`.
+
+```js
+var xhr = require('xhr')
+var qs = require('qs')
+
+xhr.queryStringStringify = qs.stringify
+
+xhr.get('/foo', {
+  qs: {
+    bar: true
+  }
+})
+```
+
 ## MIT Licenced
 
   [1]: http://xhr.spec.whatwg.org/#the-send()-method

index.js

@@ -7,6 +7,7 @@ var xtend = require("xtend")
 module.exports = createXHR
 createXHR.XMLHttpRequest = window.XMLHttpRequest || noop
 createXHR.XDomainRequest = "withCredentials" in (new createXHR.XMLHttpRequest()) ? createXHR.XMLHttpRequest : window.XDomainRequest
+createXHR.queryStringStringify = null // Define this as a function to support the `qs` option
 
 forEachArray(["get", "put", "post", "patch", "head", "delete"], function(method) {
     createXHR[method === "delete" ? "del" : method] = function(uri, options, callback) {
@@ -139,9 +140,17 @@ function _createXHR(options) {
         }
     }
 
+    var qsStringifyDefined = isFunction(createXHR.queryStringStringify);
+
+    if (options.qs && !qsStringifyDefined) {
+      throw new Error("You passed a 'qs' option, but did not define an 'xhr.queryStringStringify' function.\nYou must either omit the 'qs' option, or define 'xhr.queryStringStringify'.")
+    }
+
+    var qs = options.qs && qsStringifyDefined ? '?' + createXHR.queryStringStringify(options.qs) : '';
+
     var key
     var aborted
-    var uri = xhr.url = options.uri || options.url
+    var uri = xhr.url = (options.uri || options.url) + qs
     var method = xhr.method = options.method || "GET"
     var body = options.body || options.data
     var headers = xhr.headers = options.headers || {}