Simplify _findTopQuoteAggId call in fetchAndSetQuotes (#9542)

app/scripts/controllers/swaps.js

@@ -164,33 +164,23 @@ export default class SwapsController {
       }
     }
 
-    let topAggIdData
-    let topAggId
-    let isBest
+    let topAggId = null
 
     // We can reduce time on the loading screen by only doing this after the
     // loading screen and best quote have rendered.
     if (!approvalRequired && !fetchParams?.balanceError) {
       newQuotes = await this.getAllQuotesWithGasEstimates(newQuotes)
+    }
 
-      if (Object.values(newQuotes).length === 0) {
-        this.setSwapsErrorKey(QUOTES_NOT_AVAILABLE_ERROR)
-      } else {
-        const {
-          topAggId: topAggIdAfterModifications,
-          isBest: isBestAfterModifications,
-        } = await this._findTopQuoteAggId(newQuotes)
-        topAggId = topAggIdAfterModifications
-        isBest = isBestAfterModifications
-      }
+    if (Object.values(newQuotes).length === 0) {
+      this.setSwapsErrorKey(QUOTES_NOT_AVAILABLE_ERROR)
     } else {
-      topAggIdData = await this._findTopQuoteAggId(newQuotes)
-      topAggId = topAggIdData.topAggId
-      isBest = topAggIdData.isBest
-    }
+      const topAggData = await this._findTopQuoteAggId(newQuotes)
 
-    if (isBest) {
-      newQuotes[topAggId].isBestQuote = true
+      if (topAggData.topAggId) {
+        topAggId = topAggData.topAggId
+        newQuotes[topAggId].isBestQuote = topAggData.isBest
+      }
     }
 
     const { swapsState } = this.store.getState()

test/unit/app/controllers/swaps-test.js

@@ -404,7 +404,7 @@ describe('SwapsController', function () {
         assert.strictEqual(newQuotes[topAggId].isBestQuote, true)
       })
 
-      it('does not set isBestQuote if no conversion rate exists for destination token', async function () {
+      it('does not mark as best quote if no conversion rate exists for destination token', async function () {
         fetchTradesInfoStub.resolves(MOCK_QUOTES)
 
         // Make it so approval is not required
@@ -420,7 +420,7 @@ describe('SwapsController', function () {
           MOCK_FETCH_METADATA,
         )
 
-        assert.strictEqual(newQuotes[topAggId].isBestQuote, undefined)
+        assert.strictEqual(newQuotes[topAggId].isBestQuote, false)
       })
     })