Refactor session validation logic in Phase Service / AuthComponent

src/app/auth/auth.component.ts

@@ -8,12 +8,12 @@ import { GithubService } from '../core/services/github.service';
 import { PhaseService } from '../core/services/phase.service';
 import { Title } from '@angular/platform-browser';
 import { Profile } from './profiles/profiles.component';
-import { flatMap, map } from 'rxjs/operators';
+import { flatMap } from 'rxjs/operators';
 import { UserService } from '../core/services/user.service';
 import { GithubEventService } from '../core/services/githubevent.service';
 import { ElectronService } from '../core/services/electron.service';
 import { ApplicationService } from '../core/services/application.service';
-import { session } from 'electron';
+import { throwIfFalse } from '../shared/lib/custom-ops';
 import { GithubUser } from '../core/models/github-user.model';
 
 const appSetting = require('../../../package.json');
@@ -170,11 +170,8 @@ export class AuthComponent implements OnInit, OnDestroy {
     this.githubService.storeOrganizationDetails(org, dataRepo);
 
     this.phaseService.storeSessionData().pipe(
-      map((isValidSession: boolean) => {
-        if (!isValidSession) {
-          throw new Error('Invalid Session');
-        }
-      })
+      throwIfFalse(isValidSession => isValidSession,
+                   () => new Error('Invalid Session'))
     ).subscribe(() => {
       this.auth.startOAuthProcess();
     }, (error) => {

src/app/core/models/session.model.ts

@@ -0,0 +1,38 @@
+import { pipe } from 'rxjs';
+import { throwIfFalse } from '../../shared/lib/custom-ops';
+
+export interface SessionData {
+  openPhases: string[];
+  phaseBugReporting: string;
+  phaseTeamResponse: string;
+  phaseTesterResponse: string;
+  phaseModeration: string;
+}
+
+export function assertSessionDataIntegrity() {
+  return pipe(
+    throwIfFalse(sessionData => sessionData !== undefined,
+      () => new Error('Session Data Unavailable')),
+    throwIfFalse(isSessionDataCorrectlyDefined,
+      () => new Error('Session Data is Incorrectly Defined')),
+    throwIfFalse(hasOpenPhases,
+      () => new Error('There are no accessible phases.')));
+}
+
+/**
+ * Ensures that the input session Data has been correctly defined.
+ * Returns true if satisfies these properties, false otherwise.
+ * @param sessionData
+ */
+function isSessionDataCorrectlyDefined(sessionData: SessionData): boolean {
+  for (const data of Object.values(sessionData)) {
+    if (data === undefined || data === '') {
+      return false;
+    }
+  }
+  return true;
+}
+
+function hasOpenPhases(sessionData: SessionData): boolean {
+  return sessionData.openPhases.length !== 0;
+}

src/app/core/services/phase.service.ts

@@ -6,6 +6,7 @@ import { GithubService } from './github.service';
 import { LabelService } from './label.service';
 import { UserService } from './user.service';
 import { UserRole } from '../models/user.model';
+import { SessionData, assertSessionDataIntegrity } from '../models/session.model';
 import { MatDialog } from '@angular/material';
 import { SessionFixConfirmationComponent } from './session-fix-confirmation/session-fix-confirmation.component';
 
@@ -16,15 +17,6 @@ export enum Phase {
   phaseModeration = 'phaseModeration'
 }
 
-
-export interface SessionData {
-  openPhases: string[];
-  phaseBugReporting: string;
-  phaseTeamResponse: string;
-  phaseTesterResponse: string;
-  phaseModeration: string;
-}
-
 @Injectable({
   providedIn: 'root',
 })
@@ -89,8 +81,8 @@ export class PhaseService {
    */
   storeSessionData(): Observable<boolean> {
     return this.fetchSessionData().pipe(
+      assertSessionDataIntegrity(),
       map((sessionData: SessionData) => {
-        this.assertSessionDataIntegrity(sessionData);
         this.updateSessionParameters(sessionData);
         return this.currentPhase !== undefined;
       })
@@ -109,14 +101,6 @@ export class PhaseService {
     }
   }
 
-  assertSessionDataIntegrity(sessionData: SessionData): void {
-    if (sessionData === undefined) {
-      throw new Error('Session Data Unavailable.');
-    } else if (!this.isSessionDataCorrectlyDefined(sessionData)) {
-      throw new Error('Session Data is Incorrectly Defined');
-    }
-  }
-
   /**
    * Checks if the necessary repository is available and creates it if the permissions are available.
    * @param sessionData
@@ -145,30 +129,12 @@ export class PhaseService {
     });
   }
 
-  /**
-   * Ensures that the input session Data has been correctly defined.
-   * Returns true if satisfies these properties, false otherwise.
-   * @param sessionData
-   */
-  isSessionDataCorrectlyDefined(sessionData: SessionData): boolean {
-    for (const data of Object.values(sessionData)) {
-      if (data === undefined || data === '') {
-        return false;
-      }
-    }
-    return true;
-  }
 
   /**
    * Stores session data and sets current session's phase.
-   * @throws Error - If there are no open phases in this session.
    * @param sessionData
    */
   updateSessionParameters(sessionData: SessionData) {
-    if (sessionData.openPhases.length === 0) {
-      throw new Error('There are no accessible phases.');
-    }
-
     this.sessionData = sessionData;
     this.currentPhase = Phase[sessionData.openPhases[0]];
     this.repoName = sessionData[sessionData.openPhases[0]];
@@ -194,8 +160,8 @@ export class PhaseService {
    */
   sessionSetup(): Observable<any> {
     return this.fetchSessionData().pipe(
+      assertSessionDataIntegrity(),
       flatMap((sessionData: SessionData) => {
-        this.assertSessionDataIntegrity(sessionData);
         this.updateSessionParameters(sessionData);
         return this.verifySessionAvailability(sessionData);
       }),

src/app/shared/lib/custom-ops.ts

@@ -0,0 +1,9 @@
+import { filter, throwIfEmpty } from 'rxjs/operators';
+import { pipe } from 'rxjs';
+
+export function throwIfFalse(predicate, error_func) {
+    return pipe(
+        filter(v => predicate(v)),
+        throwIfEmpty(error_func)
+    );
+}