feat(Singleton): add singleton support

README.md

@@ -23,13 +23,15 @@ yarn add @incognia/api
 Require the package:
 
 CommonJS modules:
+
 ```js
 const { IncogniaApi } = require('@incognia/api')
 ```
 
 Or ES modules:
+
 ```js
-import { IncogniaApi } from "@incognia/api";
+import { IncogniaApi } from '@incognia/api'
 ```
 
 Instantiate with your clientId and clientSecret:
@@ -41,6 +43,18 @@ const incogniaApi = new IncogniaApi({
 })
 ```
 
+Additionally, the Incognia API instance can be stored in a global instance as follows. This implementation makes
+sure that a single Incognia API client is created and used.
+
+```js
+IncogniaApi.setSingletonInstance(
+  new IncogniaApi({ clientId: 'clientId', clientSecret: 'clientSecret' })
+)
+
+// Retrieves the stored instance
+const incogniaApi = IncogniaApi.getSingletonInstance()
+```
+
 ## API methods
 
 ### Registering a Mobile Signup
@@ -77,7 +91,7 @@ This method registers a new web signup for the given session token, returning a
 ```js
 try {
   const signup = await incogniaApi.registerWebSignup({
-    sessionToken: 'session_token',
+    sessionToken: 'session_token'
   })
 } catch (error) {
   console.log(error.message)
@@ -108,14 +122,13 @@ This method registers a new web login for the given session token and account, r
 try {
   const login = await incogniaApi.registerWebLogin({
     sessionToken: 'session_token',
-    accountId: 'account_id',
+    accountId: 'account_id'
   })
 } catch (error) {
   console.log(error.message)
 }
 ```
 
-
 ### Registering a Payment
 
 This method registers a new payment for the given installation and account, returning a transaction assessment, containing the risk assessment and supporting evidence.

src/incogniaApi.ts

@@ -56,6 +56,37 @@ export const apiEndpoints: ApiEndpoints = {
 }
 
 export class IncogniaApi {
+  /*
+   ** Singleton support
+   */
+
+  private static instance?: IncogniaApi
+
+  public static setSingletonInstance(instance: IncogniaApi): void {
+    if (!IncogniaApi.instance) {
+      if (!instance) {
+        throw new IncogniaError(
+          'No instance provided to set as singleton instance'
+        )
+      }
+      IncogniaApi.instance = instance
+    }
+  }
+
+  public static getSingletonInstance(): IncogniaApi {
+    if (!IncogniaApi.instance) {
+      throw new IncogniaError('No singleton instance set')
+    }
+    return IncogniaApi.instance
+  }
+
+  public static resetSingletonInstance(): void {
+    IncogniaApi.instance = undefined
+  }
+
+  /*
+   ** Implementation
+   */
   readonly clientId: string
   readonly clientSecret: string
   incogniaToken: IncogniaToken | null

test/incogniaApi.test.ts

@@ -24,7 +24,7 @@ const credentials = {
   clientSecret: 'clientSecret'
 }
 
-describe('API', () => {
+describe('IncogniaApi', () => {
   beforeEach(() => {
     nock.cleanAll()
     incogniaApi = new IncogniaApi(credentials)
@@ -236,7 +236,7 @@ describe('API', () => {
         )
 
         const expectedData = {
-          event: FeedbackEvent.AccountTakeover,
+          event: FeedbackEvent.AccountTakeover
         }
 
         const expectedParams = {
@@ -265,8 +265,8 @@ describe('API', () => {
             paymentId: 'payment_id',
             signupId: 'signup_id',
             timestamp: 123,
-            occurredAt: new Date("Jul 19 2024 01:02:03 UTC"),
-            expiresAt:  new Date("Jul 30 2024 01:02:03 UTC"),
+            occurredAt: new Date('Jul 19 2024 01:02:03 UTC'),
+            expiresAt: new Date('Jul 30 2024 01:02:03 UTC')
           },
           {
             dryRun: true
@@ -402,4 +402,35 @@ describe('API', () => {
       expect(initIncognia).toThrowError(IncogniaError)
     })
   })
+
+  describe('Singleton support', () => {
+    beforeEach(() => IncogniaApi.resetSingletonInstance())
+
+    it('sets and gets the singleton instance', () => {
+      IncogniaApi.setSingletonInstance(incogniaApi)
+
+      const newClient = new IncogniaApi(credentials)
+      IncogniaApi.setSingletonInstance(newClient)
+
+      expect(IncogniaApi.getSingletonInstance()).toEqual(incogniaApi)
+    })
+
+    it('throws an error when no singleton instance is set', () => {
+      const getSingletonInstance = () => {
+        IncogniaApi.getSingletonInstance()
+      }
+      expect(getSingletonInstance).toThrow('No singleton instance set')
+      expect(getSingletonInstance).toThrowError(IncogniaError)
+    })
+
+    it('throws an error when no instance is provided', () => {
+      const setSingletonInstance = () => {
+        IncogniaApi.setSingletonInstance(null as any)
+      }
+      expect(setSingletonInstance).toThrow(
+        'No instance provided to set as singleton instance'
+      )
+      expect(setSingletonInstance).toThrowError(IncogniaError)
+    })
+  })
 })