CurrencyController can be configured to always fetch usd rate (MetaMa…

…sk#292)

* CurrencyController can be configured to always fetch usd rate in addition to currentCurrency rate

* Update unit tests

Co-authored-by: Mark Stacey <markjstacey@gmail.com>

src/assets/CurrencyRateController.ts

@@ -11,11 +11,13 @@ const { Mutex } = require('await-semaphore');
  * @property currentCurrency - Currently-active ISO 4217 currency code
  * @property interval - Polling interval used to fetch new currency rate
  * @property nativeCurrency - Symbol for the base asset used for conversion
+ * @property includeUSDRate - Whether to include the usd rate in addition to the currentCurrency
  */
 export interface CurrencyRateConfig extends BaseConfig {
   currentCurrency: string;
   interval: number;
   nativeCurrency: string;
+  includeUSDRate?: boolean;
 }
 
 /**
@@ -27,19 +29,24 @@ export interface CurrencyRateConfig extends BaseConfig {
  * @property conversionRate - Conversion rate from current base asset to the current currency
  * @property currentCurrency - Currently-active ISO 4217 currency code
  * @property nativeCurrency - Symbol for the base asset used for conversion
+ * @property usdConversionRate - Conversion rate from usd to the current currency
  */
 export interface CurrencyRateState extends BaseState {
   conversionDate: number;
   conversionRate: number;
   currentCurrency: string;
   nativeCurrency: string;
+  usdConversionRate?: number;
 }
 
 /**
  * Controller that passively polls on a set interval for an exchange rate from the current base
  * asset to the current currency
  */
 export class CurrencyRateController extends BaseController<CurrencyRateConfig, CurrencyRateState> {
+  /* Optional config to include conversion to usd in all price url fetches and on state */
+  includeUSDRate?: boolean;
+
   private activeCurrency = '';
 
   private activeNativeCurrency = '';
@@ -52,10 +59,11 @@ export class CurrencyRateController extends BaseController<CurrencyRateConfig, C
     return state && state.currentCurrency ? state.currentCurrency : 'usd';
   }
 
-  private getPricingURL(currentCurrency: string, nativeCurrency: string) {
+  private getPricingURL(currentCurrency: string, nativeCurrency: string, includeUSDRate?: boolean) {
     return (
       `https://min-api.cryptocompare.com/data/price?fsym=` +
-      `${nativeCurrency.toUpperCase()}&tsyms=${currentCurrency.toUpperCase()}`
+      `${nativeCurrency.toUpperCase()}&tsyms=${currentCurrency.toUpperCase()}` +
+      `${includeUSDRate && currentCurrency.toUpperCase() !== 'USD' ? ',USD' : ''}`
     );
   }
 
@@ -77,12 +85,14 @@ export class CurrencyRateController extends BaseController<CurrencyRateConfig, C
       disabled: true,
       interval: 180000,
       nativeCurrency: 'ETH',
+      includeUSDRate: false,
     };
     this.defaultState = {
       conversionDate: 0,
       conversionRate: 0,
       currentCurrency: this.defaultConfig.currentCurrency,
       nativeCurrency: this.defaultConfig.nativeCurrency,
+      usdConversionRate: 0,
     };
     this.initialize();
     this.configure({ disabled: false }, false, false);
@@ -128,21 +138,26 @@ export class CurrencyRateController extends BaseController<CurrencyRateConfig, C
    *
    * @param currency - ISO 4217 currency code
    * @param nativeCurrency - Symbol for base asset
+   * @param includeUSDRate - Whether to add the USD rate to the fetch
    * @returns - Promise resolving to exchange rate for given currency
    */
-  async fetchExchangeRate(currency: string, nativeCurrency = this.activeNativeCurrency): Promise<CurrencyRateState> {
-    const json = await handleFetch(this.getPricingURL(currency, nativeCurrency));
+  async fetchExchangeRate(currency: string, nativeCurrency = this.activeNativeCurrency, includeUSDRate?: boolean): Promise<CurrencyRateState> {
+    const json = await handleFetch(this.getPricingURL(currency, nativeCurrency, includeUSDRate));
     const conversionRate = Number(json[currency.toUpperCase()]);
-
+    const usdConversionRate = Number(json.USD);
     if (!Number.isFinite(conversionRate)) {
       throw new Error(`Invalid response for ${currency.toUpperCase()}: ${json[currency.toUpperCase()]}`);
     }
+    if (includeUSDRate && !Number.isFinite(usdConversionRate)) {
+      throw new Error(`Invalid response for usdConversionRate: ${json.USD}`);
+    }
 
     return {
       conversionDate: Date.now() / 1000,
       conversionRate,
       currentCurrency: currency,
       nativeCurrency,
+      usdConversionRate,
     };
   }
 
@@ -157,16 +172,19 @@ export class CurrencyRateController extends BaseController<CurrencyRateConfig, C
     }
     const releaseLock = await this.mutex.acquire();
     try {
-      const { conversionDate, conversionRate } = await this.fetchExchangeRate(
+      const { conversionDate, conversionRate, usdConversionRate } = await this.fetchExchangeRate(
         this.activeCurrency,
         this.activeNativeCurrency,
+        this.includeUSDRate,
       );
-      this.update({
+      const newState: CurrencyRateState = {
         conversionDate,
         conversionRate,
         currentCurrency: this.activeCurrency,
         nativeCurrency: this.activeNativeCurrency,
-      });
+        usdConversionRate: this.includeUSDRate ? usdConversionRate : this.defaultState.usdConversionRate,
+      };
+      this.update(newState);
 
       return this.state;
     } finally {

tests/ComposableController.test.ts

@@ -40,6 +40,7 @@ describe('ComposableController', () => {
         conversionRate: 0,
         currentCurrency: 'usd',
         nativeCurrency: 'ETH',
+        usdConversionRate: 0,
       },
       EnsController: {
         ensEntries: {},
@@ -96,6 +97,7 @@ describe('ComposableController', () => {
       selectedAddress: '',
       suggestedAssets: [],
       tokens: [],
+      usdConversionRate: 0,
     });
   });
 
@@ -149,6 +151,7 @@ describe('ComposableController', () => {
       selectedAddress: '',
       suggestedAssets: [],
       tokens: [],
+      usdConversionRate: 0,
     });
   });
 

tests/CurrencyRateController.test.ts

@@ -5,7 +5,11 @@ import CurrencyRateController from '../src/assets/CurrencyRateController';
 
 describe('CurrencyRateController', () => {
   beforeEach(() => {
-    fetchMock.mock('*', () => new Response(JSON.stringify({ USD: 1337 }))).spy();
+    fetchMock
+      .mock(/XYZ,USD/u, () => new Response(JSON.stringify({ XYZ: 123, USD: 456 })))
+      .mock(/DEF,USD/u, () => new Response(JSON.stringify({ DEF: 123 })))
+      .mock('*', () => new Response(JSON.stringify({ USD: 1337 })))
+      .spy();
   });
 
   afterEach(() => {
@@ -19,6 +23,7 @@ describe('CurrencyRateController', () => {
       conversionRate: 0,
       currentCurrency: 'usd',
       nativeCurrency: 'ETH',
+      usdConversionRate: 0,
     });
   });
 
@@ -29,6 +34,7 @@ describe('CurrencyRateController', () => {
       disabled: false,
       interval: 180000,
       nativeCurrency: 'ETH',
+      includeUSDRate: false,
     });
   });
 
@@ -40,6 +46,7 @@ describe('CurrencyRateController', () => {
       disabled: false,
       interval: 180000,
       nativeCurrency: 'ETH',
+      includeUSDRate: false,
     });
   });
 
@@ -89,13 +96,42 @@ describe('CurrencyRateController', () => {
     expect(controller.state.conversionRate).toBeGreaterThan(0);
   });
 
+  it('should add usd rate to state when includeUSDRate is configured true', async () => {
+    const controller = new CurrencyRateController({ includeUSDRate: true, currentCurrency: 'xyz' });
+    expect(controller.state.usdConversionRate).toEqual(0);
+    await controller.updateExchangeRate();
+    expect(controller.state.usdConversionRate).toEqual(456);
+  });
+
   it('should use default base asset', async () => {
     const nativeCurrency = 'FOO';
     const controller = new CurrencyRateController({ nativeCurrency });
     await controller.fetchExchangeRate('usd');
     expect(fetchMock.calls()[0][0]).toContain(nativeCurrency);
   });
 
+  it('should add usd rate to state fetches when configured', async () => {
+    const controller = new CurrencyRateController({ includeUSDRate: true });
+    const result = await controller.fetchExchangeRate('xyz', 'FOO', true);
+    expect(fetchMock.calls()[0][0]).toContain('XYZ,USD');
+    expect(result.usdConversionRate).toEqual(456);
+    expect(result.conversionRate).toEqual(123);
+  });
+
+  it('should throw correctly when configured to return usd but receives an invalid response for currentCurrency rate', async () => {
+    const controller = new CurrencyRateController({ includeUSDRate: true });
+    await expect(controller.fetchExchangeRate('abc', 'FOO', true)).rejects.toThrow(
+      'Invalid response for ABC: undefined',
+    );
+  });
+
+  it('should throw correctly when configured to return usd but receives an invalid response for usdConversionRate', async () => {
+    const controller = new CurrencyRateController({ includeUSDRate: true });
+    await expect(controller.fetchExchangeRate('def', 'FOO', true)).rejects.toThrow(
+      'Invalid response for usdConversionRate: undefined',
+    );
+  });
+
   describe('#fetchExchangeRate', () => {
     it('should handle a valid symbol in the API response', async () => {
       const controller = new CurrencyRateController({ nativeCurrency: 'usd' });