address comments

Signed-off-by: Won Jun Jang <wjang@uber.com>

src/samplers/remote_sampler.js

@@ -93,10 +93,10 @@ export default class RemoteControlledSampler {
 
   _refreshSamplingStrategy() {
     let serviceName: string = encodeURIComponent(this._serviceName);
-    let success: Function = body => {
+    const success: Function = body => {
       this._parseSamplingServerResponse(body);
     };
-    let error: Function = err => {
+    const error: Function = err => {
       this._logger.error(`Error in fetching sampling strategy: ${err}.`);
       this._metrics.samplerQueryFailure.increment(1);
     };

src/throttler/default_throttler.js

@@ -17,7 +17,7 @@
 export default class DefaultThrottler {
   _throttleAll: boolean;
 
-  constructor(throttleAll: ?boolean) {
+  constructor(throttleAll?: boolean) {
     this._throttleAll = throttleAll || false;
   }
 

src/throttler/remote_throttler.js

@@ -168,7 +168,7 @@ export default class RemoteThrottler {
     }
   }
 
-  close(callback: ?Function): void {
+  close(callback?: Function): void {
     clearTimeout(this._initialDelayTimeoutHandle);
     clearInterval(this._refreshIntervalHandle);
 

test/lib/config_server.js

@@ -23,7 +23,7 @@ export default class ConfigServer {
   constructor(port: number = 5778) {
     this._port = port;
     this._app = express();
-    this._strategies = Object.create(null);
+    this._strategies = {};
     this._app.get('/sampling', this._handleSampling.bind(this));
     this._app.get('/credits', this._handleThrottling.bind(this));
   }
@@ -37,8 +37,8 @@ export default class ConfigServer {
   }
 
   clearConfigs(): void {
-    this._strategies = Object.create(null);
-    this._credits = Object.create(null);
+    this._strategies = {};
+    this._credits = {};
   }
 
   _handleSampling(req: any, res: any) {
@@ -54,8 +54,8 @@ export default class ConfigServer {
   }
 
   _handle(req: any, res: any, getFunc: Function) {
-    let service = req.query.service;
-    let resp = getFunc(service);
+    const service = req.query.service;
+    const resp = getFunc(service);
     if (resp) {
       res.send(resp);
     } else {

test/throttler/remote_throttler.js

@@ -35,6 +35,7 @@ describe('RemoteThrottler should', () => {
   let operation = 'op';
   let other_operation = 'oop';
   let uuid = 'uuid';
+  let creditsUpdatedHook;
 
   before(() => {
     server = new ConfigServer().start();
@@ -53,6 +54,7 @@ describe('RemoteThrottler should', () => {
       initialDelayMs: 60000,
       metrics: metrics,
       logger: logger,
+      onCreditsUpdate: (...args) => creditsUpdatedHook(...args),
     });
   });
 
@@ -63,7 +65,7 @@ describe('RemoteThrottler should', () => {
   it('return false for isAllowed on initial call and return true once credits are initialized', done => {
     throttler.setProcess({ uuid: uuid });
     server.addCredits(serviceName, [{ operation: operation, credits: 3 }]);
-    throttler._onCreditsUpdate = _throttler => {
+    creditsUpdatedHook = _throttler => {
       assert.isOk(_throttler.isAllowed(operation));
       assert.equal(_throttler._credits[operation], 2);
       assert.equal(LocalBackend.counterValue(metrics.throttlerUpdateSuccess), 1);
@@ -106,7 +108,7 @@ describe('RemoteThrottler should', () => {
     ]);
     throttler._credits[operation] = 0;
     throttler._credits[other_operation] = 0;
-    throttler._onCreditsUpdate = _throttler => {
+    creditsUpdatedHook = _throttler => {
       assert.isOk(_throttler.isAllowed(operation));
       assert.equal(_throttler._credits[operation], 4);
       assert.isOk(_throttler.isAllowed(other_operation));
@@ -160,7 +162,7 @@ describe('RemoteThrottler should', () => {
     throttler.setProcess({ uuid: uuid });
     throttler._credits[operation] = 0;
     server.addCredits(serviceName, [{ operation: operation, credits: 5 }]);
-    throttler._onCreditsUpdate = _throttler => {
+    creditsUpdatedHook = _throttler => {
       assert.isOk(_throttler.isAllowed(operation));
       assert.equal(_throttler._credits[operation], 4);
       assert.equal(LocalBackend.counterValue(metrics.throttlerUpdateSuccess), 1);