Add user collections method

README.md

@@ -70,7 +70,7 @@ import Unsplash from 'unsplash-js/native';
 Generate an authentication url with the scopes your app requires.
 
 ```js
-let authenticationUrl = unsplash.auth.getAuthenticationUrl([
+const authenticationUrl = unsplash.auth.getAuthenticationUrl([
   "public",
   "read_user",
   "write_user",
@@ -133,7 +133,7 @@ __Arguments__
 
 __Example__
 ```js
-let authenticationUrl = unsplash.auth.getAuthenticationUrl([
+const authenticationUrl = unsplash.auth.getAuthenticationUrl([
   "public",
   "read_user",
   "write_user",
@@ -289,6 +289,27 @@ unsplash.users.likes("naoufal", 2, 15, "popular")
 ```
 ---
 
+### users.collections(username, page, perPage)
+Get a list of photos liked by a user.
+
+__Arguments__
+
+| Argument | Type | Opt/Required | Notes |
+|---|---|---|---|
+|__`username`__|_string_|Required||
+|__`page`__|_number_|Optional||
+|__`perPage`__|_number_|Optional||
+
+__Example__
+```js
+unsplash.users.collections("naoufal", 2, 15)
+  .then(toJson)
+  .then(json => {
+    // Your code
+  });
+```
+---
+
 <div id="photos" />
 
 ### photos.listPhotos(page, perPage)
@@ -760,7 +781,7 @@ __Example__
 ```js
 import Unsplash, { toJson } from "unsplash-js";
 
-let unsplash = new Unsplash({
+const unsplash = new Unsplash({
   applicationId: "{YOUR_APPLICATION_ID}",
   secret: "{YOUR_SECRET_KEY}",
   callbackUrl: "{YOUR_CALLBACK_URL}"

src/methods/users.js

@@ -34,6 +34,20 @@ export default function users(): Object {
         order_by: orderBy
       };
 
+      return this.request({
+        url,
+        method: "GET",
+        query
+      });
+    },
+
+    collections: (username: string, page: number = 1, perPage: number = 10) => {
+      const url = `/users/${username}/collections`;
+      const query = {
+        page,
+        per_page: perPage
+      };
+
       return this.request({
         url,
         method: "GET",

test/unsplash-test.js

@@ -267,6 +267,23 @@ describe("Unsplash", () => {
         }]);
       });
     });
+
+    describe("collections", () => {
+      it("should make a GET request to /users/{username}/collections", () => {
+        let spy = spyOn(unsplash, "request");
+        unsplash.users.collections("naoufal");
+
+        expect(spy.calls.length).toEqual(1);
+        expect(spy.calls[0].arguments).toEqual([{
+          method: "GET",
+          url: "/users/naoufal/collections",
+          query: {
+            page: 1,
+            per_page: 10
+          }
+        }]);
+      });
+    });
   });
 
   describe("photos", () => {