Only save successful assets to the asset caches

Assets that cannot have not found a rate, like obscure or invalid tokens, shouldn't slow down the initial lookup on login. Also, we were previously storing pairs in the cache along with dates which meant historical rates were being queried as well.

Fix eslint error in exchangeRates.ts

Author: peachbits

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased (develop)
 
+- changed: Optimize exchange rate fetching and asset pair cache handling
 - fixed: Fixed broken `logEvent` tracking calls by adding the needed `dispatch`.
 - removed: Remove change quote tracking.
 

eslint.config.mjs

@@ -496,7 +496,6 @@ export default [
       'src/util/CurrencyInfoHelpers.ts',
       'src/util/CurrencyWalletHelpers.ts',
 
-      'src/util/exchangeRates.ts',
       'src/util/fake/FakeProviders.tsx',
       'src/util/FioAddressUtils.ts',
       'src/util/getAccountUsername.ts',

src/actions/ExchangeRateActions.ts

@@ -6,6 +6,7 @@ import type { ThunkAction } from '../types/reduxTypes'
 import {
   asCryptoAsset,
   asRatesParams,
+  createRateKey,
   type RatesParams
 } from '../util/exchangeRates'
 import { fetchRates } from '../util/network'
@@ -308,6 +309,8 @@ async function fetchExchangeRates(
     }
   }
 
+  const cryptoPairCache = new Map<string, CryptoFiatPair>()
+  const fiatPairCache = new Map<string, FiatFiatPair>()
   const requests = convertToRatesParams(cryptoPairMap, fiatPairMap)
   const promises = requests.map(async query => {
     const options = {
@@ -362,6 +365,14 @@ async function fetchExchangeRates(
           }
 
           rateObj.expiration = rateExpiration
+
+          // Save crypto assets with rates to asset cache
+          cryptoPairCache.set(createRateKey(cryptoRate.asset, targetFiat), {
+            asset: cryptoRate.asset,
+            targetFiat,
+            isoDate: undefined,
+            expiration: pairExpiration
+          })
         }
         for (const fiatRate of cleanedRates.fiat) {
           const { isoDate, rate } = fiatRate
@@ -398,6 +409,14 @@ async function fetchExchangeRates(
           }
 
           rateObj.expiration = rateExpiration
+
+          // Save fiat assets with rates to asset cache
+          fiatPairCache.set(createRateKey(fiatCode, targetFiat), {
+            fiatCode,
+            targetFiat,
+            isoDate: undefined,
+            expiration: pairExpiration
+          })
         }
       }
     } catch (error: unknown) {
@@ -411,8 +430,8 @@ async function fetchExchangeRates(
   // Update the in-memory cache:
   exchangeRateCache = {
     rates,
-    cryptoPairs: Array.from(cryptoPairMap.values()),
-    fiatPairs: Array.from(fiatPairMap.values())
+    cryptoPairs: Array.from(cryptoPairCache.values()),
+    fiatPairs: Array.from(fiatPairCache.values())
   }
 
   // Write the cache to disk:

src/util/exchangeRates.ts

@@ -127,7 +127,7 @@ const doQuery = async (doFetch?: EdgeFetchFunction): Promise<void> => {
 
               clog(`${n} deleting ${key}`)
               resolverMap.delete(key)
-              if (resolvers.length) {
+              if (resolvers.length > 0) {
                 resolvers.forEach((r, i) => {
                   r(rate)
                 })
@@ -163,7 +163,7 @@ const doQuery = async (doFetch?: EdgeFetchFunction): Promise<void> => {
 
               clog(`${n} deleting ${key}`)
               resolverMap.delete(key)
-              if (resolvers.length) {
+              if (resolvers.length > 0) {
                 resolvers.forEach((r, i) => {
                   r(rate)
                 })
@@ -205,7 +205,7 @@ const addToQueue = (
   resolve: Function,
   maxQuerySize: number,
   doFetch?: EdgeFetchFunction
-) => {
+): void => {
   const rateKeyResolver = resolverMap.get(rateKey)
   if (rateKeyResolver == null) {
     // Create a new entry in the map for this pair/date
@@ -229,7 +229,7 @@ const addToQueue = (
   }
 }
 
-const createRateKey = (
+export const createRateKey = (
   asset: { pluginId: string; tokenId?: EdgeTokenId } | string,
   targetFiat: string,
   date?: string