chore(lint): Enable no-return-assign except-parens.

.eslintrc

@@ -117,6 +117,7 @@
     "no-octal-escape": 2,
     "no-path-concat": 2,
     "no-proto": 2,
+    "no-return-assign": [2, "except-parens"],
     "no-script-url": 2,
     "no-self-compare": 2,
     "no-sequences": 2,

lib/PreviewProvider.js

@@ -82,7 +82,8 @@ PreviewProvider.prototype = {
       // filter out the allowed query params and update the query string
       newURL.search = Array.from(queryParams.keys())
         .filter(param => ALLOWED_QUERY_PARAMS.has(param))
-        .map(param => param = param + "=" + queryParams.get(param)).join("&");
+        .map(param => param + "=" + queryParams.get(param))
+        .join("&");
     }
 
     // remove extra slashes then construct back a safe pathname

test/test-ExperimentProvider.js

@@ -25,7 +25,7 @@ const DEFAULT_TEST_EXPERIMENTS = {
 let experimentProvider;
 
 function setup(clientID = DEFAULT_CLIENT_ID, experiments = DEFAULT_TEST_EXPERIMENTS, n) {
-  return experimentProvider = new ExperimentProvider(clientID, experiments, n && (() => n));
+  return (experimentProvider = new ExperimentProvider(clientID, experiments, n && (() => n)));
 }
 
 exports["test ExperimentProvider"] = assert => {

test/test-PreviewProvider.js

@@ -49,7 +49,7 @@ exports.test_only_request_links_once = function*(assert) {
         )
     );
     // count the times each url has been requested
-    data.urls.forEach(url => urlsRequested[url] = (urlsRequested[url] + 1) || 1);
+    data.urls.forEach(url => (urlsRequested[url] = (urlsRequested[url] + 1) || 1));
     response.setHeader("Content-Type", "application/json", false);
     response.write(JSON.stringify({"urls": {urlsRequested}}));
   });