From 7c9ee78402a85cf16db7511c5baae833d0a01485 Mon Sep 17 00:00:00 2001
From: Md Junaed Hossain <169046794+junaed-optimizely@users.noreply.github.com>
Date: Sat, 14 Dec 2024 00:11:18 +0600
Subject: [PATCH] [FSSDK-10935] log adjustment

---
 lib/error_messages.ts                         | 17 +++++++++---
 lib/exception_messages.ts                     |  5 ++++
 lib/index.browser.tests.js                    |  5 ++--
 lib/log_messages.ts                           |  6 +++++
 .../odp_event_api_manager.spec.ts             |  4 +--
 .../event_manager/odp_event_manager.spec.ts   |  5 ++--
 lib/odp/event_manager/odp_event_manager.ts    | 27 ++++++++++++-------
 lib/odp/odp_manager.spec.ts                   |  7 ++---
 lib/odp/odp_manager.ts                        |  3 ++-
 .../odp_segment_api_manager.spec.ts           |  3 ++-
 lib/optimizely/index.ts                       |  5 ++--
 ...onfig_manager_factory.react_native.spec.ts |  2 +-
 .../polling_datafile_manager.ts               | 18 ++++++++-----
 lib/project_config/project_config_manager.ts  | 14 ++++++----
 .../browser_request_handler.ts                |  3 ++-
 lib/vuid/vuid_manager_factory.node.spec.ts    |  3 ++-
 lib/vuid/vuid_manager_factory.node.ts         |  3 ++-
 17 files changed, 86 insertions(+), 44 deletions(-)

diff --git a/lib/error_messages.ts b/lib/error_messages.ts
index 1a48f3832..29fcb8b41 100644
--- a/lib/error_messages.ts
+++ b/lib/error_messages.ts
@@ -49,6 +49,8 @@ export const NO_EVENT_PROCESSOR = 'No event processor is provided';
 export const NO_VARIATION_FOR_EXPERIMENT_KEY = '%s: No variation key %s defined in datafile for experiment %s.';
 export const ODP_CONFIG_NOT_AVAILABLE = '%s: ODP is not integrated to the project.';
 export const ODP_EVENT_FAILED = 'ODP event send failed.';
+export const ODP_EVENT_MANAGER_IS_NOT_RUNNING = 'ODP event manager is not running.';
+export const ODP_EVENTS_SHOULD_HAVE_ATLEAST_ONE_KEY_VALUE = 'ODP events should have at least one key-value pair in identifiers.';
 export const ODP_FETCH_QUALIFIED_SEGMENTS_SEGMENTS_MANAGER_MISSING =
   '%s: ODP unable to fetch qualified segments (Segments Manager not initialized).';
 export const ODP_IDENTIFY_FAILED_EVENT_MANAGER_MISSING =
@@ -93,7 +95,14 @@ export const INVALID_INPUT_FORMAT = '%s: Provided %s is in an invalid format.';
 export const INVALID_DATAFILE_VERSION =
   '%s: This version of the JavaScript SDK does not support the given datafile version: %s';
 export const INVALID_VARIATION_KEY = '%s: Provided variation key is in an invalid format.';
-export const UNABLE_TO_GET_VUID = 'Unable to get VUID - ODP Manager is not instantiated yet.'
-export const ERROR_FETCHING_DATAFILE = 'Error fetching datafile: %s'
-export const DATAFILE_FETCH_REQUEST_FAILED = 'Datafile fetch request failed with status: %s'
-export const ONRUNNING_ERROR = 'onRunning error'
+export const UNABLE_TO_GET_VUID = 'Unable to get VUID - ODP Manager is not instantiated yet.';
+export const ERROR_FETCHING_DATAFILE = 'Error fetching datafile: %s';
+export const DATAFILE_FETCH_REQUEST_FAILED = 'Datafile fetch request failed with status: %s';
+export const ONRUNNING_ERROR = 'onRunning error';
+export const EVENT_DATA_FOUND_TO_BE_INVALID = 'Event data found to be invalid.';
+export const EVENT_ACTION_INVALID = 'Event action invalid.';
+export const FAILED_TO_SEND_ODP_EVENTS = 'failed to send odp events';
+export const UNABLE_TO_OVERWRITE_GLOBAL_WINDOW = 'Unable to overwrite global.window.';
+export const UNABLE_TO_GET_VUID_VUID_MANAGER_NOT_AVAILABLE = 'Unable to get VUID - VuidManager is not available'
+    
+    
diff --git a/lib/exception_messages.ts b/lib/exception_messages.ts
index 405670406..83965589f 100644
--- a/lib/exception_messages.ts
+++ b/lib/exception_messages.ts
@@ -23,16 +23,20 @@ export const SEND_BEACON_FAILED = 'sendBeacon failed';
 export const CANNOT_START_WITHOUT_ODP_CONFIG = 'cannot start without ODP config';
 export const START_CALLED_WHEN_ODP_IS_NOT_INTEGRATED = 'start() called when ODP is not integrated';
 export const ODP_ACTION_IS_NOT_VALID = 'ODP action is not valid (cannot be empty).';
+export const ODP_MANAGER_STOPPED_BEFORE_RUNNING = 'odp manager stopped before running';
+export const ODP_EVENT_MANAGER_STOPPED = "ODP event manager stopped before it could start";
 export const ONREADY_TIMEOUT_EXPIRED = 'onReady timeout expired after %s ms';
 export const INSTANCE_CLOSED = 'Instance closed';
 export const DATAFILE_MANAGER_STOPPED = 'Datafile manager stopped before it could be started';
 export const DATAFILE_MANAGER_FAILED_TO_START = 'Datafile manager failed to start';
 export const FAILED_TO_FETCH_DATAFILE = 'Failed to fetch datafile';
+export const FAILED_TO_START = 'Failed to start';
 export const FAILED_TO_STOP = 'Failed to stop';
 export const YOU_MUST_PROVIDE_DATAFILE_IN_SSR = 'You must provide datafile in SSR';
 export const YOU_MUST_PROVIDE_AT_LEAST_ONE_OF_SDKKEY_OR_DATAFILE = 'You must provide at least one of sdkKey or datafile';
 export const RETRY_CANCELLED = 'Retry cancelled';
 export const REQUEST_ERROR = 'Request error';
+export const REQUEST_FAILED = 'Request failed';
 export const UNSUPPORTED_PROTOCOL = 'Unsupported protocol: %s';
 export const REQUEST_TIMEOUT = 'Request timed out';
 export const NO_STATUS_CODE_IN_RESPONSE = 'No status code in response';
@@ -40,3 +44,4 @@ export const MODULE_NOT_FOUND_REACT_NATIVE_ASYNC_STORAGE = 'Module not found: @r
 export const MODULE_NOT_FOUND_REACT_NATIVE_NETINFO = 'Module not found: @react-native-community/netinfo';
 export const INVALID_CONFIG_OR_SOMETHING = 'Invalid config or something';
 export const PROMISE_SHOULD_NOT_HAVE_RESOLVED = 'Promise should not have resolved';
+export const VUID_IS_NOT_SUPPORTED_IN_NODEJS= 'VUID is not supported in Node.js environment';
diff --git a/lib/index.browser.tests.js b/lib/index.browser.tests.js
index 6facf2278..57990d5bd 100644
--- a/lib/index.browser.tests.js
+++ b/lib/index.browser.tests.js
@@ -24,8 +24,7 @@ import optimizelyFactory from './index.browser';
 import configValidator from './utils/config_validator';
 import { getMockProjectConfigManager } from './tests/mock/mock_project_config_manager';
 import { createProjectConfig } from './project_config/project_config';
-import { ODP_EVENT_FAILED_ODP_MANAGER_MISSING } from './error_messages';
-import { ODP_DISABLED, ODP_SEND_EVENT_IDENTIFIER_CONVERSION_FAILED } from './log_messages';
+import { UNABLE_TO_OVERWRITE_GLOBAL_WINDOW } from './error_messages';
 import { INVALID_CONFIG_OR_SOMETHING } from './exception_messages';
 
 
@@ -57,7 +56,7 @@ if (!global.window) {
       localStorage: new MockLocalStorage(),
     };
   } catch (e) {
-    console.error('Unable to overwrite global.window.');
+    console.error(UNABLE_TO_OVERWRITE_GLOBAL_WINDOW);
   }
 }
 
diff --git a/lib/log_messages.ts b/lib/log_messages.ts
index faa180656..e5cdbd2fe 100644
--- a/lib/log_messages.ts
+++ b/lib/log_messages.ts
@@ -123,3 +123,9 @@ export const UPDATED_OPTIMIZELY_CONFIG = '%s: Updated Optimizely config to revis
 export const OUT_OF_BOUNDS =
   '%s: Audience condition %s evaluated to UNKNOWN because the number value for user attribute "%s" is not in the range [-2^53, +2^53].';
 export const UNABLE_TO_ATTACH_UNLOAD = '%s: unable to bind optimizely.close() to page unload event: "%s"';
+export const UNABLE_TO_PARSE_AND_SKIPPED_HEADER = 'Unable to parse & skipped header item';
+export const ADDING_AUTHORIZATION_HEADER_WITH_BEARER_TOKEN = 'Adding Authorization header with Bearer Token';
+export const MAKING_DATAFILE_REQ_TO_URL_WITH_HEADERS = 'Making datafile request to url %s with headers: %s';
+export const RESPONSE_STATUS_CODE = 'Response status code: %s';
+export const SAVED_LAST_MODIFIED_HEADER_VALUE_FROM_RESPONSE  = 'Saved last modified header value from response: %s'; 
+
diff --git a/lib/odp/event_manager/odp_event_api_manager.spec.ts b/lib/odp/event_manager/odp_event_api_manager.spec.ts
index 8f6a07fd2..55ec009e1 100644
--- a/lib/odp/event_manager/odp_event_api_manager.spec.ts
+++ b/lib/odp/event_manager/odp_event_api_manager.spec.ts
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 import { describe, it, expect, vi } from 'vitest';
 
 import { DefaultOdpEventApiManager, eventApiRequestGenerator, pixelApiRequestGenerator } from './odp_event_api_manager';
@@ -42,6 +41,7 @@ const PIXEL_URL = 'https://odp.pixel.com';
 const odpConfig = new OdpConfig(API_KEY, API_HOST, PIXEL_URL, []);
 
 import { getMockRequestHandler } from '../../tests/mock/mock_request_handler';
+import { REQUEST_FAILED } from '../../exception_messages';
 
 describe('DefaultOdpEventApiManager', () => {
   it('should generate the event request using the correct odp config and event', async () => {
@@ -101,7 +101,7 @@ describe('DefaultOdpEventApiManager', () => {
   it('should return a promise that fails if the requestHandler response promise fails', async () => {
     const mockRequestHandler = getMockRequestHandler();
     mockRequestHandler.makeRequest.mockReturnValue({
-      responsePromise: Promise.reject(new Error('Request failed')),
+      responsePromise: Promise.reject(new Error(REQUEST_FAILED)),
     });
     const requestGenerator = vi.fn().mockReturnValue({
       method: 'PATCH',
diff --git a/lib/odp/event_manager/odp_event_manager.spec.ts b/lib/odp/event_manager/odp_event_manager.spec.ts
index dfe8d496a..f0acb144a 100644
--- a/lib/odp/event_manager/odp_event_manager.spec.ts
+++ b/lib/odp/event_manager/odp_event_manager.spec.ts
@@ -23,6 +23,7 @@ import { OdpEvent } from './odp_event';
 import { OdpConfig } from '../odp_config';
 import { EventDispatchResponse } from './odp_event_api_manager';
 import { advanceTimersByTime } from '../../../tests/testUtils';
+import { FAILED_TO_DISPATCH_EVENTS } from '../../exception_messages';
 
 const API_KEY = 'test-api-key';
 const API_HOST = 'https://odp.example.com';
@@ -604,7 +605,7 @@ describe('DefaultOdpEventManager', () => {
     const repeater = getMockRepeater();
 
     const apiManager = getMockApiManager();
-    apiManager.sendEvents.mockReturnValue(Promise.reject(new Error('Failed to dispatch events')));
+    apiManager.sendEvents.mockReturnValue(Promise.reject(new Error(FAILED_TO_DISPATCH_EVENTS)));
 
     const backoffController = {
       backoff: vi.fn().mockReturnValue(666),
@@ -706,7 +707,7 @@ describe('DefaultOdpEventManager', () => {
     const repeater = getMockRepeater();
 
     const apiManager = getMockApiManager();
-    apiManager.sendEvents.mockReturnValue(Promise.reject(new Error('Failed to dispatch events')));
+    apiManager.sendEvents.mockReturnValue(Promise.reject(new Error(FAILED_TO_DISPATCH_EVENTS)));
 
     const backoffController = {
       backoff: vi.fn().mockReturnValue(666),
diff --git a/lib/odp/event_manager/odp_event_manager.ts b/lib/odp/event_manager/odp_event_manager.ts
index 286c181ef..6ebe5aaa0 100644
--- a/lib/odp/event_manager/odp_event_manager.ts
+++ b/lib/odp/event_manager/odp_event_manager.ts
@@ -23,7 +23,16 @@ import { Producer } from '../../utils/type';
 import { runWithRetry } from '../../utils/executor/backoff_retry_runner';
 import { isSuccessStatusCode } from '../../utils/http_request_handler/http_util';
 import { ODP_DEFAULT_EVENT_TYPE, ODP_USER_KEY } from '../constant';
-import { ODP_NOT_INTEGRATED } from '../../error_messages';
+import {
+  EVENT_ACTION_INVALID,
+  EVENT_DATA_FOUND_TO_BE_INVALID,
+  FAILED_TO_SEND_ODP_EVENTS,
+  ODP_EVENT_MANAGER_IS_NOT_RUNNING,
+  ODP_EVENTS_SHOULD_HAVE_ATLEAST_ONE_KEY_VALUE,
+  ODP_NOT_INTEGRATED,
+} from '../../error_messages';
+import { sprintf } from '../../utils/fns';
+import { FAILED_TO_DISPATCH_EVENTS_WITH_ARG, ODP_EVENT_MANAGER_STOPPED } from '../../exception_messages';
 
 export interface OdpEventManager extends Service {
   updateConfig(odpIntegrationConfig: OdpIntegrationConfig): void;
@@ -66,8 +75,7 @@ export class DefaultOdpEventManager extends BaseService implements OdpEventManag
   private async executeDispatch(odpConfig: OdpConfig, batch: OdpEvent[]): Promise<unknown> {
     const res = await this.apiManager.sendEvents(odpConfig, batch);
     if (res.statusCode && !isSuccessStatusCode(res.statusCode)) {
-      // TODO: replace message with imported constants
-      return Promise.reject(new Error(`Failed to dispatch events: ${res.statusCode}`));
+      return Promise.reject(new Error(sprintf(FAILED_TO_DISPATCH_EVENTS_WITH_ARG, res.statusCode)));
     }
     return await Promise.resolve(res);
   }
@@ -89,8 +97,7 @@ export class DefaultOdpEventManager extends BaseService implements OdpEventManag
     return runWithRetry(
       () => this.executeDispatch(odpConfig, batch), this.retryConfig.backoffProvider(), this.retryConfig.maxRetries
     ).result.catch((err) => {
-      // TODO: replace with imported constants
-      this.logger?.error('failed to send odp events', err);
+      this.logger?.error(FAILED_TO_SEND_ODP_EVENTS, err);
     });
   }
 
@@ -139,7 +146,7 @@ export class DefaultOdpEventManager extends BaseService implements OdpEventManag
     }
 
     if (this.isNew()) {
-      this.startPromise.reject(new Error('odp event manager stopped before it could start'));
+      this.startPromise.reject(new Error(ODP_EVENT_MANAGER_STOPPED));
     }
 
     this.flush();
@@ -149,7 +156,7 @@ export class DefaultOdpEventManager extends BaseService implements OdpEventManag
 
   sendEvent(event: OdpEvent): void {
     if (!this.isRunning()) {
-      this.logger?.error('ODP event manager is not running.');
+      this.logger?.error(ODP_EVENT_MANAGER_IS_NOT_RUNNING);
       return;
     }
 
@@ -159,17 +166,17 @@ export class DefaultOdpEventManager extends BaseService implements OdpEventManag
     }
 
     if (event.identifiers.size === 0) {
-      this.logger?.error('ODP events should have at least one key-value pair in identifiers.');
+      this.logger?.error(ODP_EVENTS_SHOULD_HAVE_ATLEAST_ONE_KEY_VALUE);
       return;
     }
 
     if (!this.isDataValid(event.data)) {
-      this.logger?.error('Event data found to be invalid.');
+      this.logger?.error(EVENT_DATA_FOUND_TO_BE_INVALID);
       return;
     } 
 
     if (!event.action ) {
-      this.logger?.error('Event action invalid.');
+      this.logger?.error(EVENT_ACTION_INVALID);
       return;
     }
 
diff --git a/lib/odp/odp_manager.spec.ts b/lib/odp/odp_manager.spec.ts
index 2464bc28b..8895abcd1 100644
--- a/lib/odp/odp_manager.spec.ts
+++ b/lib/odp/odp_manager.spec.ts
@@ -25,6 +25,7 @@ import { ODP_USER_KEY } from './constant';
 import { OptimizelySegmentOption } from './segment_manager/optimizely_segment_option';
 import { OdpEventManager } from './event_manager/odp_event_manager';
 import { CLIENT_VERSION, JAVASCRIPT_CLIENT_ENGINE } from '../utils/enums';
+import { FAILED_TO_START, FAILED_TO_STOP } from '../exception_messages';
 
 const keyA = 'key-a';
 const hostA = 'host-a';
@@ -166,7 +167,7 @@ describe('DefaultOdpManager', () => {
     await exhaustMicrotasks();
 
     expect(odpManager.getState()).toEqual(ServiceState.Starting);
-    eventManagerPromise.reject(new Error('Failed to start'));
+    eventManagerPromise.reject(new Error(FAILED_TO_START));
 
     await expect(odpManager.onRunning()).rejects.toThrow();
     await expect(odpManager.onTerminated()).rejects.toThrow();
@@ -186,7 +187,7 @@ describe('DefaultOdpManager', () => {
     odpManager.start();
     expect(odpManager.getState()).toEqual(ServiceState.Starting);
 
-    eventManagerPromise.reject(new Error('Failed to start'));
+    eventManagerPromise.reject(new Error(FAILED_TO_START));
 
     await expect(odpManager.onRunning()).rejects.toThrow();
     await expect(odpManager.onTerminated()).rejects.toThrow();
@@ -692,7 +693,7 @@ describe('DefaultOdpManager', () => {
     await exhaustMicrotasks();
     expect(odpManager.getState()).toEqual(ServiceState.Stopping);
 
-    eventManagerTerminatedPromise.reject(new Error('Failed to stop'));
+    eventManagerTerminatedPromise.reject(new Error(FAILED_TO_STOP));
     await expect(odpManager.onTerminated()).rejects.toThrow();
   });
 });
diff --git a/lib/odp/odp_manager.ts b/lib/odp/odp_manager.ts
index 560e445a4..05c476ff3 100644
--- a/lib/odp/odp_manager.ts
+++ b/lib/odp/odp_manager.ts
@@ -29,6 +29,7 @@ import { CLIENT_VERSION, JAVASCRIPT_CLIENT_ENGINE } from '../utils/enums';
 import { ODP_DEFAULT_EVENT_TYPE, ODP_EVENT_ACTION, ODP_USER_KEY } from './constant';
 import { isVuid } from '../vuid/vuid';
 import { Maybe } from '../utils/type';
+import { ODP_MANAGER_STOPPED_BEFORE_RUNNING } from '../exception_messages';
 
 export interface OdpManager extends Service {
   updateConfig(odpIntegrationConfig: OdpIntegrationConfig): boolean;
@@ -131,7 +132,7 @@ export class DefaultOdpManager extends BaseService implements OdpManager {
     }
 
     if (!this.isRunning()) {
-      this.startPromise.reject(new Error('odp manager stopped before running'));
+      this.startPromise.reject(new Error(ODP_MANAGER_STOPPED_BEFORE_RUNNING));
     }
 
     this.state = ServiceState.Stopping;
diff --git a/lib/odp/segment_manager/odp_segment_api_manager.spec.ts b/lib/odp/segment_manager/odp_segment_api_manager.spec.ts
index 52237add9..cc5e8782c 100644
--- a/lib/odp/segment_manager/odp_segment_api_manager.spec.ts
+++ b/lib/odp/segment_manager/odp_segment_api_manager.spec.ts
@@ -20,6 +20,7 @@ import { ODP_USER_KEY } from '../constant';
 import { getMockRequestHandler } from '../../tests/mock/mock_request_handler';
 import { getMockLogger } from '../../tests/mock/mock_logger';
 import { DefaultOdpSegmentApiManager } from './odp_segment_api_manager';
+import { REQUEST_TIMEOUT } from '../../exception_messages';
 
 const API_KEY = 'not-real-api-key';
 const GRAPHQL_ENDPOINT = 'https://some.example.com/graphql/endpoint';
@@ -46,7 +47,7 @@ describe('DefaultOdpSegmentApiManager', () => {
     const requestHandler = getMockRequestHandler();
     requestHandler.makeRequest.mockReturnValue({
       abort: () => {},
-      responsePromise: Promise.reject(new Error('Request timed out')),
+      responsePromise: Promise.reject(new Error(REQUEST_TIMEOUT)),
     });
     const logger = getMockLogger();
     const manager = new DefaultOdpSegmentApiManager(requestHandler, logger);
diff --git a/lib/optimizely/index.ts b/lib/optimizely/index.ts
index e16a5e135..34fa116f6 100644
--- a/lib/optimizely/index.ts
+++ b/lib/optimizely/index.ts
@@ -73,7 +73,7 @@ import {
   NO_EVENT_PROCESSOR,
   ODP_EVENT_FAILED,
   ODP_EVENT_FAILED_ODP_MANAGER_MISSING,
-  UNABLE_TO_GET_VUID,
+  UNABLE_TO_GET_VUID_VUID_MANAGER_NOT_AVAILABLE,
 } from '../error_messages';
 import {
   EVENT_KEY_NOT_FOUND,
@@ -86,7 +86,6 @@ import {
   INVALID_OBJECT,
   NOT_ACTIVATING_USER,
   NOT_TRACKING_USER,
-  ODP_SEND_EVENT_IDENTIFIER_CONVERSION_FAILED,
   SHOULD_NOT_DISPATCH_ACTIVATE,
   TRACK_EVENT,
   UNRECOGNIZED_DECIDE_OPTION,
@@ -1736,7 +1735,7 @@ export default class Optimizely implements Client {
    */
   public getVuid(): string | undefined {
     if (!this.vuidManager) {
-      this.logger?.error('Unable to get VUID - VuidManager is not available');
+      this.logger?.error(UNABLE_TO_GET_VUID_VUID_MANAGER_NOT_AVAILABLE);
       return undefined;
     }
 
diff --git a/lib/project_config/config_manager_factory.react_native.spec.ts b/lib/project_config/config_manager_factory.react_native.spec.ts
index 5ea2d56e3..5a88bb015 100644
--- a/lib/project_config/config_manager_factory.react_native.spec.ts
+++ b/lib/project_config/config_manager_factory.react_native.spec.ts
@@ -30,7 +30,7 @@ async function mockRequireAsyncStorage() {
   M._load = (uri: string, parent: string) => {
     if (uri === '@react-native-async-storage/async-storage') {
       if (isAsyncStorageAvailable) return { default: {} };
-      throw new Error('Module not found: @react-native-async-storage/async-storage');
+      throw new Error(MODULE_NOT_FOUND_REACT_NATIVE_ASYNC_STORAGE);
     }
     return M._load_original(uri, parent);
   };
diff --git a/lib/project_config/polling_datafile_manager.ts b/lib/project_config/polling_datafile_manager.ts
index 6d05b89ec..bde704029 100644
--- a/lib/project_config/polling_datafile_manager.ts
+++ b/lib/project_config/polling_datafile_manager.ts
@@ -25,6 +25,12 @@ import { Consumer, Fn } from '../utils/type';
 import { isSuccessStatusCode } from '../utils/http_request_handler/http_util';
 import { DATAFILE_MANAGER_STOPPED, FAILED_TO_FETCH_DATAFILE } from '../exception_messages';
 import { DATAFILE_FETCH_REQUEST_FAILED, ERROR_FETCHING_DATAFILE } from '../error_messages';
+import {
+  ADDING_AUTHORIZATION_HEADER_WITH_BEARER_TOKEN,
+  MAKING_DATAFILE_REQ_TO_URL_WITH_HEADERS,
+  RESPONSE_STATUS_CODE,
+  SAVED_LAST_MODIFIED_HEADER_VALUE_FROM_RESPONSE,
+} from '../log_messages';
 
 export class PollingDatafileManager extends BaseService implements DatafileManager {
   private requestHandler: RequestHandler;
@@ -98,8 +104,8 @@ export class PollingDatafileManager extends BaseService implements DatafileManag
     if (this.isNew() || this.isStarting()) {
       this.startPromise.reject(new Error(DATAFILE_MANAGER_STOPPED));
     }
-    // Todo: Replace this with constant
-    this.logger?.debug('Datafile manager stopped');
+    
+    this.logger?.debug(DATAFILE_MANAGER_STOPPED);
     this.state = ServiceState.Terminated;
     this.repeater.stop();
     this.currentRequest?.abort();
@@ -169,11 +175,11 @@ export class PollingDatafileManager extends BaseService implements DatafileManag
     }
 
     if (this.datafileAccessToken) {
-      this.logger?.debug('Adding Authorization header with Bearer Token');
+      this.logger?.debug(ADDING_AUTHORIZATION_HEADER_WITH_BEARER_TOKEN);
       headers['Authorization'] = `Bearer ${this.datafileAccessToken}`;
     }
 
-    this.logger?.debug('Making datafile request to url %s with headers: %s', this.datafileUrl, () => JSON.stringify(headers));
+    this.logger?.debug(MAKING_DATAFILE_REQ_TO_URL_WITH_HEADERS, this.datafileUrl, () => JSON.stringify(headers));
     return this.requestHandler.makeRequest(this.datafileUrl, headers, 'GET');
   }
 
@@ -200,7 +206,7 @@ export class PollingDatafileManager extends BaseService implements DatafileManag
   }
   
   private getDatafileFromResponse(response: Response): string | undefined{
-    this.logger?.debug('Response status code: %s', response.statusCode);
+    this.logger?.debug(RESPONSE_STATUS_CODE, response.statusCode);
     if (response.statusCode === 304) {
       return undefined;
     }
@@ -211,7 +217,7 @@ export class PollingDatafileManager extends BaseService implements DatafileManag
     const lastModifiedHeader = headers['last-modified'] || headers['Last-Modified'];
     if (lastModifiedHeader !== undefined) {
       this.lastResponseLastModified = lastModifiedHeader;
-      this.logger?.debug('Saved last modified header value from response: %s', this.lastResponseLastModified);
+      this.logger?.debug(SAVED_LAST_MODIFIED_HEADER_VALUE_FROM_RESPONSE, this.lastResponseLastModified);
     }
   }
 
diff --git a/lib/project_config/project_config_manager.ts b/lib/project_config/project_config_manager.ts
index 7e1f59a14..81ee87b78 100644
--- a/lib/project_config/project_config_manager.ts
+++ b/lib/project_config/project_config_manager.ts
@@ -22,7 +22,12 @@ import { scheduleMicrotask } from '../utils/microtask';
 import { Service, ServiceState, BaseService } from '../service';
 import { Consumer, Fn, Transformer } from '../utils/type';
 import { EventEmitter } from '../utils/event_emitter/event_emitter';
-import { DATAFILE_MANAGER_FAILED_TO_START, DATAFILE_MANAGER_STOPPED } from '../exception_messages';
+import {
+  DATAFILE_MANAGER_FAILED_TO_START,
+  DATAFILE_MANAGER_STOPPED,
+  YOU_MUST_PROVIDE_AT_LEAST_ONE_OF_SDKKEY_OR_DATAFILE,
+  YOU_MUST_PROVIDE_DATAFILE_IN_SSR,
+} from '../exception_messages';
 
 interface ProjectConfigManagerConfig {
   // TODO: Don't use object type
@@ -79,9 +84,9 @@ export class ProjectConfigManagerImpl extends BaseService implements ProjectConf
 
     if (!this.datafile && !this.datafileManager) {
       const errorMessage = this.isSsr
-        ? 'You must provide datafile in SSR'
-        : 'You must provide at least one of sdkKey or datafile';
-      // TODO: replace message with imported constants
+        ? YOU_MUST_PROVIDE_DATAFILE_IN_SSR
+        : YOU_MUST_PROVIDE_AT_LEAST_ONE_OF_SDKKEY_OR_DATAFILE;
+      
       this.handleInitError(new Error(errorMessage));
       return;
     }
@@ -114,7 +119,6 @@ export class ProjectConfigManagerImpl extends BaseService implements ProjectConf
   }
 
   private handleDatafileManagerError(err: Error): void {
-    // TODO: replace message with imported constants
     this.logger?.error(DATAFILE_MANAGER_FAILED_TO_START, err);
 
     // If datafile manager onRunning() promise is rejected, and the project config manager 
diff --git a/lib/utils/http_request_handler/browser_request_handler.ts b/lib/utils/http_request_handler/browser_request_handler.ts
index 06b9606d6..26e22425d 100644
--- a/lib/utils/http_request_handler/browser_request_handler.ts
+++ b/lib/utils/http_request_handler/browser_request_handler.ts
@@ -18,6 +18,7 @@ import { AbortableRequest, Headers, RequestHandler, Response } from './http';
 import { LogHandler, LogLevel } from '../../modules/logging';
 import { REQUEST_TIMEOUT_MS } from '../enums';
 import { REQUEST_ERROR, REQUEST_TIMEOUT } from '../../exception_messages';
+import { UNABLE_TO_PARSE_AND_SKIPPED_HEADER } from '../../log_messages';
 
 /**
  * Handles sending requests and receiving responses over HTTP via XMLHttpRequest
@@ -123,7 +124,7 @@ export class BrowserRequestHandler implements RequestHandler {
           }
         }
       } catch {
-        this.logger?.log(LogLevel.WARNING, `Unable to parse & skipped header item '${headerLine}'`);
+        this.logger?.log(LogLevel.WARNING, UNABLE_TO_PARSE_AND_SKIPPED_HEADER, headerLine);
       }
     });
     return headers;
diff --git a/lib/vuid/vuid_manager_factory.node.spec.ts b/lib/vuid/vuid_manager_factory.node.spec.ts
index 2a81f9a8a..048704794 100644
--- a/lib/vuid/vuid_manager_factory.node.spec.ts
+++ b/lib/vuid/vuid_manager_factory.node.spec.ts
@@ -17,10 +17,11 @@
 import { vi, describe, expect, it } from 'vitest';
 
 import { createVuidManager } from './vuid_manager_factory.node';
+import { VUID_IS_NOT_SUPPORTED_IN_NODEJS } from '../exception_messages';
 
 describe('createVuidManager', () => {
   it('should throw an error', () => {
     expect(() => createVuidManager({ enableVuid: true }))
-      .toThrowError('VUID is not supported in Node.js environment');
+      .toThrowError(VUID_IS_NOT_SUPPORTED_IN_NODEJS);
   });
 });
diff --git a/lib/vuid/vuid_manager_factory.node.ts b/lib/vuid/vuid_manager_factory.node.ts
index 993fbb60a..6d194ce0b 100644
--- a/lib/vuid/vuid_manager_factory.node.ts
+++ b/lib/vuid/vuid_manager_factory.node.ts
@@ -13,10 +13,11 @@
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
+import { VUID_IS_NOT_SUPPORTED_IN_NODEJS } from '../exception_messages';
 import { VuidManager } from './vuid_manager';
 import { VuidManagerOptions } from './vuid_manager_factory';
 
 export const createVuidManager = (options: VuidManagerOptions): VuidManager => {
-  throw new Error('VUID is not supported in Node.js environment');
+  throw new Error(VUID_IS_NOT_SUPPORTED_IN_NODEJS);
 };