Prevent querystrings from starting with &

Fixes #1953

client/app/scripts/utils/__tests__/web-api-utils-test.js

@@ -1,5 +1,7 @@
 jest.dontMock('../web-api-utils');
 
+import {OrderedMap as makeOrderedMap} from 'immutable';
+
 describe('WebApiUtils', () => {
   const WebApiUtils = require('../web-api-utils');
 
@@ -22,4 +24,19 @@ describe('WebApiUtils', () => {
       expect(basePath('/')).toBe('');
     });
   });
+
+  describe('buildOptionsQuery', () => {
+    const buildOptionsQuery = WebApiUtils.buildOptionsQuery;
+
+    it('should handle empty options', () => {
+      expect(buildOptionsQuery(makeOrderedMap({}))).toBe('');
+    });
+
+    it('should combine multiple options', () => {
+      expect(buildOptionsQuery(makeOrderedMap([
+        ['foo', 2],
+        ['bar', 4]
+      ]))).toBe('foo=2&bar=4');
+    });
+  });
 });

client/app/scripts/utils/web-api-utils.js

@@ -25,9 +25,9 @@ let controlErrorTimer = 0;
 let createWebsocketAt = 0;
 let firstMessageOnWebsocketAt = 0;
 
-function buildOptionsQuery(options) {
+export function buildOptionsQuery(options) {
   if (options) {
-    return options.reduce((query, value, param) => `${query}&${param}=${value}`, '');
+    return options.map((value, param) => `${param}=${value}`).join('&');
   }
   return '';
 }