fix(redirect-controller): proper handling of undefined values

opengovsg · Jul 28, 2021 · 515b444 · 515b444
1 parent c12d491
commit 515b444
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Showing 4 changed files with 23 additions and 11 deletions.
diff --git a/src/server/modules/redirect/__tests__/RedirectController.test.ts b/src/server/modules/redirect/__tests__/RedirectController.test.ts
@@ -187,18 +187,24 @@ const mockAnalyticsLogger: jest.Mocked<AnalyticsLoggerService> = {
 }
 
 // eslint-disable-next-line no-unused-vars
-const writeShortlinkToCookie = jest.fn((_: string[] | null, __: string) => [])
+const writeShortlinkToCookie = jest.fn(
+  (_: string[] | undefined, __: string) => [],
+)
 
 const cookieArrayReducerMockUnvisited: jest.Mocked<CookieArrayReducerService> =
   {
     // eslint-disable-next-line no-unused-vars
-    userHasVisitedShortlink: jest.fn((_: string[] | null, __: string) => false),
+    userHasVisitedShortlink: jest.fn(
+      (_: string[] | undefined, __: string) => false,
+    ),
     writeShortlinkToCookie,
   }
 
 const cookieArrayReducerMockVisited: jest.Mocked<CookieArrayReducerService> = {
   // eslint-disable-next-line no-unused-vars
-  userHasVisitedShortlink: jest.fn((_: string[] | null, __: string) => true),
+  userHasVisitedShortlink: jest.fn(
+    (_: string[] | undefined, __: string) => true,
+  ),
   writeShortlinkToCookie,
 }
 

diff --git a/src/server/modules/redirect/services/CookieArrayReducerService.ts b/src/server/modules/redirect/services/CookieArrayReducerService.ts
@@ -12,12 +12,18 @@ import { cookieSessionMaxSizeBytes } from '../../../config'
   ["userHasVisitedShortlink", "writeShortlinkToCookie"] }] */
 @injectable()
 export class CookieArrayReducerService {
-  userHasVisitedShortlink(cookie: string[] | null, shortUrl: string): boolean {
+  userHasVisitedShortlink(
+    cookie: string[] | undefined,
+    shortUrl: string,
+  ): boolean {
     if (!cookie) return false
     return cookie.includes(shortUrl)
   }
 
-  writeShortlinkToCookie(cookie: string[] | null, shortUrl: string): string[] {
+  writeShortlinkToCookie(
+    cookie: string[] | undefined,
+    shortUrl: string,
+  ): string[] {
     if (!cookie) return [shortUrl]
     if (cookie.includes(shortUrl)) {
       return _.without(cookie, shortUrl).concat(shortUrl)

diff --git a/src/server/modules/redirect/services/RedirectService.ts b/src/server/modules/redirect/services/RedirectService.ts
@@ -34,7 +34,7 @@ export class RedirectService {
 
   public redirectFor: (
     shortUrl: string,
-    pastVisits: string[],
+    pastVisits: string[] | undefined,
     userAgent: string,
     referrer: string,
   ) => Promise<RedirectResult> = async (
@@ -59,7 +59,7 @@ export class RedirectService {
     if (this.crawlerCheckService.isCrawler(userAgent)) {
       return {
         longUrl,
-        visitedUrls: pastVisits,
+        visitedUrls: pastVisits || [],
         redirectType: RedirectType.Direct,
       }
     }

diff --git a/src/server/modules/redirect/services/__tests__/CookieArrayReducerService.test.ts b/src/server/modules/redirect/services/__tests__/CookieArrayReducerService.test.ts
@@ -16,7 +16,7 @@ describe('CookieArrayReducerService', () => {
 
   describe('userHasVisitedShortLink', () => {
     it('is false on null cookie array', () => {
-      expect(service.userHasVisitedShortlink(null, shortUrl)).toBeFalsy()
+      expect(service.userHasVisitedShortlink(undefined, shortUrl)).toBeFalsy()
     })
 
     it('is false on empty cookie array', () => {
@@ -36,9 +36,9 @@ describe('CookieArrayReducerService', () => {
 
   describe('writeShortlinkToCookie', () => {
     it('returns array with shortUrl on null cookie', () => {
-      expect(service.writeShortlinkToCookie(null, shortUrl)).toStrictEqual([
-        shortUrl,
-      ])
+      expect(service.writeShortlinkToCookie(undefined, shortUrl)).toStrictEqual(
+        [shortUrl],
+      )
     })
 
     it('moves shortUrl to the end of cookie array', () => {