Support customizing query string in redux-resource-xhr

docs/extras/redux-resource-xhr.md

@@ -279,13 +279,46 @@ This is the library used to make HTTP requests. It is a thin wrapper around the
 library [`xhr`](https://github.com/naugtur/xhr), and supports all of the same
 options and signatures.
 
-On top of that, it adds two features:
+On top of that, it adds several new features:
 
-1. Support for a `qs` option (similar to the [`request`](https://github.com/request/request#requestoptions-callback) library).
+1. Support for query string serialization (similar to the [`request`](https://github.com/request/request#requestoptions-callback) library).
 
 2. Omitting the callback will return a native
   [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise).
 
+#### Customizing Query String Serialization
+
+If you pass a `qs` object, then the object will be serialized into a query parameter
+using the [`querystringify`](https://www.npmjs.com/package/querystringify) library. This
+library supports basic serialization, but we don't expect it to work for every API that
+you interface with.
+
+You can change how the query string is serialized using two options:
+
+- `qsStringify` - a function with the signature `(qs, options)`. It should return
+  the string to be appended to the URI.
+
+- `qsStringifyOptions` - an object that is passed as the second argument to the `qsStringify`
+  method.
+
+For instance, if you wish to use the `qs` library, you might do this:
+
+```js
+import { xhr } from 'redux-resource-xhr';
+import qs from 'qs';
+
+xhr('/books', {
+  method: 'GET',
+  qs: {
+    pageSize: 10,
+    pageNumber: 0,
+    publishers: ['goldenBooks', 'penguinBooks']
+  },
+  qsStringify: qs.stringify,
+  qsStringifyOptions: { arrayFormat: 'brackets' }
+}, cb);
+```
+
 #### Example
 
 ```js

packages/redux-resource-xhr/package.json

@@ -71,6 +71,7 @@
     "babel-register": "^6.24.1",
     "cross-env": "^5.0.1",
     "in-publish": "^2.0.0",
+    "qs": "^6.5.1",
     "rimraf": "^2.6.1",
     "rollup": "^0.45.1",
     "rollup-plugin-babel": "^2.7.1",

packages/redux-resource-xhr/src/xhr.js

@@ -9,8 +9,13 @@ import qs from 'querystringify';
 //   2. Pass a `qs` option for query string support
 
 function buildUrl(uri, options) {
+  let qsStringify = options.qsStringify || qs.stringify;
   if (options.qs) {
-    uri += qs.stringify(options.qs, true);
+    let stringified = qsStringify(options.qs, options.qsStringifyOptions);
+    if (stringified[0] !== '?') {
+      stringified = `?${stringified}`;
+    }
+    uri += stringified;
   }
   return uri;
 }

packages/redux-resource-xhr/test/unit/xhr.js

@@ -1,4 +1,5 @@
 import xhr, {__RewireAPI__} from '../../src/xhr';
+import qs from 'qs';
 
 describe('xhr', function() {
   afterEach(() => {
@@ -71,6 +72,30 @@ describe('xhr', function() {
     });
   });
 
+  describe('xhr(url, options, cb); custom query string serializer', () => {
+    it('should call xhr with the correct args', () => {
+      this.xhrStub = stub();
+      __RewireAPI__.__Rewire__('xhr', this.xhrStub);
+
+      const cb = stub();
+      const options = {
+        method: 'GET',
+        qs: {a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']]},
+        qsStringify: qs.stringify,
+        qsStringifyOptions: {encodeValuesOnly: true}
+      };
+      xhr('https://www.google.com', options, cb);
+
+      expect(this.xhrStub).to.have.been.calledWith({
+        uri: 'https://www.google.com?a=b&c[0]=d&c[1]=e%3Df&f[0][0]=g&f[1][0]=h',
+        method: 'GET',
+        qs: {a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']]},
+        qsStringify: qs.stringify,
+        qsStringifyOptions: {encodeValuesOnly: true}
+      }, cb);
+    });
+  });
+
   describe('xhr(url, cb)', () => {
     it('should call xhr with the correct args', () => {
       this.xhrStub = stub();