feat: Add endpoint to retrieve exchange rates (#767)

src/client/RESTClient.ts

@@ -16,13 +16,14 @@ import {FillAPI} from '../fill';
 import querystring from 'querystring';
 import {ProfileAPI} from '../profile';
 import axiosRetry, {isNetworkOrIdempotentRequestError} from 'axios-retry';
-import util from 'util';
+import util, {DebugLogger} from 'util';
 import {EventEmitter} from 'events';
 import {getErrorMessage, gotRateLimited, inAirPlaneMode} from '../error/ErrorUtil';
 import {CurrencyAPI} from '../currency';
 import {WithdrawAPI} from '../withdraw';
 import {TransferAPI} from '../transfer';
 import {TimeAPI} from '../time';
+import {ExchangeRateAPI} from '../exchange-rate/ExchangeRateAPI';
 
 export interface RESTClient {
   on(
@@ -46,6 +47,7 @@ export class RESTClient extends EventEmitter {
 
   readonly account: AccountAPI;
   readonly currency: CurrencyAPI;
+  readonly exchangeRate: ExchangeRateAPI;
   readonly fee: FeeAPI;
   readonly fill: FillAPI;
   readonly order: OrderAPI;
@@ -57,7 +59,7 @@ export class RESTClient extends EventEmitter {
   readonly withdraw: WithdrawAPI;
 
   private readonly httpClient: AxiosInstance;
-  private readonly logger: (msg: string, ...param: any[]) => void;
+  private readonly logger: DebugLogger;
 
   constructor(baseURL: string, private readonly signRequest: (setup: RequestSetup) => Promise<SignedRequest>) {
     super();
@@ -113,6 +115,7 @@ export class RESTClient extends EventEmitter {
 
     this.account = new AccountAPI(this.httpClient);
     this.currency = new CurrencyAPI(this.httpClient);
+    this.exchangeRate = new ExchangeRateAPI();
     this.fee = new FeeAPI(this.httpClient);
     this.fill = new FillAPI(this.httpClient);
     this.order = new OrderAPI(this.httpClient);

src/client/WebSocketClient.test.ts

@@ -63,6 +63,13 @@ describe('WebSocketClient', () => {
       const invalidUrl = 'ws://localhost:50001';
       const ws = createWebSocketClient(invalidUrl);
       ws.on(WebSocketEvent.ON_ERROR, () => {
+        /**
+         * TODO:
+         * An asynchronous function called its 'done' callback more than once. This is a bug in the spec, beforeAll,
+         * beforeEach, afterAll, or afterEach function in question. This will be treated as an error in a future
+         * version. See:
+         * https://jasmine.github.io/tutorials/upgrading_to_Jasmine_4.0#deprecations-due-to-calling-done-multiple-times
+         */
         done();
       });
       ws.connect();
@@ -93,6 +100,7 @@ describe('WebSocketClient', () => {
       done();
     });
 
+    // TODO: This test appears to be flaky
     it('returns true when called after the connection is created', done => {
       const ws = createWebSocketClient();
 
@@ -109,6 +117,7 @@ describe('WebSocketClient', () => {
       ws.connect();
     });
 
+    // TODO: This test appears to be flaky
     it('returns false when called after the connection is closed', done => {
       const ws = createWebSocketClient();
 
@@ -258,6 +267,7 @@ describe('WebSocketClient', () => {
       ws.connect();
     });
 
+    // TODO: This test appears to be flaky
     it('receives typed "snapshot" messages from "level2" channel', done => {
       const channel = {
         name: WebSocketChannelName.LEVEL2,
@@ -477,6 +487,7 @@ describe('WebSocketClient', () => {
   });
 
   describe('unsubscribe', () => {
+    // TODO: This test appears to be flaky
     it('unsubscribes from all products on a channel', done => {
       server.on('connection', socket => {
         socket.on('message', (message: string) => {
@@ -508,6 +519,7 @@ describe('WebSocketClient', () => {
   });
 
   describe('setupHeartbeat', () => {
+    // TODO: This test appears to be flaky
     it('sends ping messages within a defined interval', done => {
       server.on('connection', socket => {
         socket.on('ping', async () => {

src/exchange-rate/ExchangeRateAPI.test.ts

@@ -0,0 +1,36 @@
+import nock from 'nock';
+import getExchangeRates from '../test/fixtures/rest/v2/exchange-rates/GET-200.json';
+import getExchangeRatesEUR from '../test/fixtures/rest/v2/exchange-rates/GET-200-EUR.json';
+import {ExchangeRateAPI} from './ExchangeRateAPI';
+
+describe('ExchangeRateAPI', () => {
+  afterEach(() => nock.cleanAll());
+
+  beforeEach(() => {
+    nock.cleanAll();
+  });
+
+  describe('getExchangeRates', () => {
+    it('returns the exchange rates based on USD by default', async () => {
+      nock('https://api.coinbase.com')
+        .get(ExchangeRateAPI.URL.V2_EXCHANGE_RATES)
+        .query({currency: 'USD'})
+        .reply(200, JSON.stringify(getExchangeRates));
+
+      const rates = await global.client.rest.exchangeRate.getExchangeRates();
+      expect(rates.currency).toBe('USD');
+      expect(rates.rates['EUR']).toBe('1.0208');
+    });
+
+    it('returns the exchange rates for a specific currency', async () => {
+      nock('https://api.coinbase.com')
+        .get(ExchangeRateAPI.URL.V2_EXCHANGE_RATES)
+        .query({currency: 'EUR'})
+        .reply(200, JSON.stringify(getExchangeRatesEUR));
+
+      const rates = await global.client.rest.exchangeRate.getExchangeRates('EUR');
+      expect(rates.currency).toBe('EUR');
+      expect(rates.rates['IOTX']).toBe('29.4767870302137067');
+    });
+  });
+});

src/exchange-rate/ExchangeRateAPI.ts

@@ -0,0 +1,30 @@
+import axios from 'axios';
+
+export interface ExchangeRate {
+  currency: string;
+  rates: {[currency: string]: string};
+}
+
+/**
+ * @see https://docs.cloud.coinbase.com/sign-in-with-coinbase/docs/api-exchange-rates
+ */
+export class ExchangeRateAPI {
+  static readonly URL = {
+    V2_EXCHANGE_RATES: `/v2/exchange-rates`,
+  };
+
+  constructor(private readonly baseURL: string = 'https://api.coinbase.com') {}
+
+  /**
+   * Get current exchange rates. Default base currency is USD, but it can be defined as any supported currency.
+   * Returned rates will define the exchange rate for one unit of the base currency.
+   *
+   * @see https://docs.cloud.coinbase.com/sign-in-with-coinbase/docs/api-exchange-rates#get-exchange-rates
+   */
+  async getExchangeRates(currency: string = 'USD'): Promise<ExchangeRate> {
+    const response = await axios.get<{
+      data: ExchangeRate;
+    }>(`${this.baseURL}${ExchangeRateAPI.URL.V2_EXCHANGE_RATES}`, {params: {currency}});
+    return response.data.data;
+  }
+}