Add users endpoint to frontend API class (!11374)

app/assets/javascripts/api.js

@@ -137,6 +137,18 @@ const Api = {
       .error(callback);
   },
+  users(query, options) {
+    const url = Api.buildUrl(this.usersPath);
+    return Api.wrapAjaxCall({
+      url,
+      data: Object.assign({
+        search: query,
+        per_page: 20,
+      }, options),
+      dataType: 'json',
+    });
+  },
+
   buildUrl(url) {
     let urlRoot = '';
     if (gon.relative_url_root != null) {
@@ -144,6 +156,20 @@ const Api = {
     }
     return urlRoot + url.replace(':version', gon.api_version);
   },
+
+  wrapAjaxCall(options) {
+    return new Promise((resolve, reject) => {
+      // jQuery 2 is not Promises/A+ compatible (missing catch)
+      $.ajax(options) // eslint-disable-line promise/catch-or-return
+      .then(data => resolve(data),
+        (jqXHR, textStatus, errorThrown) => {
+          const error = new Error(`${options.url}: ${errorThrown}`);
+          error.textStatus = textStatus;
+          reject(error);
+        },
+      );
+    });
+  },
 };
 export default Api;

spec/javascripts/api_spec.js

@@ -253,4 +253,29 @@ describe('Api', () => {
       });
     });
   });
+
+  describe('users', () => {
+    it('fetches users', (done) => {
+      const query = 'dummy query';
+      const options = { unused: 'option' };
+      const expectedUrl = `${dummyUrlRoot}/api/${dummyApiVersion}/users.json`;
+      const expectedData = Object.assign({
+        search: query,
+        per_page: 20,
+      }, options);
+      spyOn(jQuery, 'ajax').and.callFake((request) => {
+        expect(request.url).toEqual(expectedUrl);
+        expect(request.dataType).toEqual('json');
+        expect(request.data).toEqual(expectedData);
+        return sendDummyResponse();
+      });
+
+      Api.users(query, options)
+        .then((response) => {
+          expect(response).toBe(dummyResponse);
+        })
+        .then(done)
+        .catch(done.fail);
+    });
+  });
 });