From afeb45efe27916db5d359b6bd58942c0ef86ffea Mon Sep 17 00:00:00 2001
From: Brad Decker <git@braddecker.dev>
Date: Tue, 9 Feb 2021 16:34:57 -0600
Subject: [PATCH] fix race condition with network switching

---
 app/scripts/controllers/token-rates.js        | 17 ++++---
 app/scripts/metamask-controller.js            |  9 +++-
 .../app/controllers/token-rates-controller.js | 46 ++++++++++++++++++-
 3 files changed, 63 insertions(+), 9 deletions(-)

diff --git a/app/scripts/controllers/token-rates.js b/app/scripts/controllers/token-rates.js
index a3f0f671094e..7505e4c843fc 100644
--- a/app/scripts/controllers/token-rates.js
+++ b/app/scripts/controllers/token-rates.js
@@ -19,10 +19,17 @@ export default class TokenRatesController {
    *
    * @param {Object} [config] - Options to configure controller
    */
-  constructor({ currency, preferences } = {}) {
+  constructor({ preferences, onNetworkDidChange, getNativeCurrency } = {}) {
     this.store = new ObservableStore();
-    this.currency = currency;
-    this.preferences = preferences;
+    this.nativeCurrency = getNativeCurrency() ?? 'ETH';
+    this.tokens = preferences.getState().tokens;
+    preferences.subscribe(({ tokens = [] }) => {
+      this.tokens = tokens;
+    });
+    onNetworkDidChange(() => {
+      this.nativeCurrency = getNativeCurrency() ?? 'ETH';
+      this.updateExchangeRates();
+    });
   }
 
   /**
@@ -30,9 +37,7 @@ export default class TokenRatesController {
    */
   async updateExchangeRates() {
     const contractExchangeRates = {};
-    const nativeCurrency = this.currency
-      ? this.currency.state.nativeCurrency.toLowerCase()
-      : 'eth';
+    const nativeCurrency = this.nativeCurrency.toLowerCase();
     const pairs = this._tokens.map((token) => token.address).join(',');
     const query = `contract_addresses=${pairs}&vs_currencies=${nativeCurrency}`;
     if (this._tokens.length > 0) {
diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index 93404fd39919..91ca1c414f30 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -169,8 +169,15 @@ export default class MetamaskController extends EventEmitter {
 
     // token exchange rate tracker
     this.tokenRatesController = new TokenRatesController({
-      currency: this.currencyRateController,
       preferences: this.preferencesController.store,
+      onNetworkDidChange: this.networkController.on.bind(
+        this.networkController,
+        NETWORK_EVENTS.NETWORK_DID_CHANGE,
+      ),
+      getNativeCurrency: () => {
+        const { ticker } = this.networkController.getProviderConfig();
+        return ticker;
+      },
     });
 
     this.ensController = new EnsController({
diff --git a/test/unit/app/controllers/token-rates-controller.js b/test/unit/app/controllers/token-rates-controller.js
index c1f69d54fba7..8015d6d5f0cd 100644
--- a/test/unit/app/controllers/token-rates-controller.js
+++ b/test/unit/app/controllers/token-rates-controller.js
@@ -4,10 +4,22 @@ import { ObservableStore } from '@metamask/obs-store';
 import TokenRatesController from '../../../../app/scripts/controllers/token-rates';
 
 describe('TokenRatesController', function () {
+  let onNetworkDidChange;
+  let nativeCurrency;
+  let getNativeCurrency;
+  beforeEach(function () {
+    onNetworkDidChange = sinon.spy();
+    nativeCurrency = 'ETH';
+    getNativeCurrency = () => nativeCurrency;
+  });
   it('should listen for preferences store updates', function () {
     const preferences = new ObservableStore({ tokens: [] });
     preferences.putState({ tokens: ['foo'] });
-    const controller = new TokenRatesController({ preferences });
+    const controller = new TokenRatesController({
+      preferences,
+      onNetworkDidChange,
+      getNativeCurrency,
+    });
     assert.deepEqual(controller._tokens, ['foo']);
   });
 
@@ -15,11 +27,41 @@ describe('TokenRatesController', function () {
     const stub = sinon.stub(global, 'setInterval');
     const preferences = new ObservableStore({ tokens: [] });
     preferences.putState({ tokens: ['foo'] });
-    const controller = new TokenRatesController({ preferences });
+    const controller = new TokenRatesController({
+      preferences,
+      onNetworkDidChange,
+      getNativeCurrency,
+    });
     controller.start(1337);
 
     assert.strictEqual(stub.getCall(0).args[1], 1337);
     stub.restore();
     controller.stop();
   });
+
+  it('should update native currency if network changes', async function () {
+    const preferences = new ObservableStore({ tokens: [] });
+    preferences.putState({ tokens: ['foo'] });
+    const controller = new TokenRatesController({
+      preferences,
+      onNetworkDidChange,
+      getNativeCurrency,
+    });
+    nativeCurrency = 'xDAI';
+    onNetworkDidChange.getCall(0).args[0]();
+    assert.strictEqual(controller.nativeCurrency, 'xDAI');
+  });
+
+  it('should update exchange rates if network changes', async function () {
+    const preferences = new ObservableStore({ tokens: [] });
+    preferences.putState({ tokens: ['foo'] });
+    const controller = new TokenRatesController({
+      preferences,
+      onNetworkDidChange,
+      getNativeCurrency,
+    });
+    sinon.spy(controller, 'updateExchangeRates');
+    onNetworkDidChange.getCall(0).args[0]();
+    assert(controller.updateExchangeRates.calledOnce);
+  });
 });