fix: condition check for null or undefined value (#45)

# 🤖 Linear

Closes ZKS-160

## Description

Fix error on `getTokenPrices` if condition check

libs/pricing/src/services/coingecko.service.ts

@@ -54,7 +54,7 @@ export class CoingeckoService implements IPricingService {
         const missingTokenIds: string[] = [];
         const cachedMap = cachedTokenPrices.reduce(
             (result, price, index) => {
-                if (price !== null) result[tokenIds.at(index) as string] = price;
+                if (price) result[tokenIds.at(index) as string] = price;
                 else missingTokenIds.push(tokenIds.at(index) as string);
 
                 return result;
@@ -69,10 +69,6 @@ export class CoingeckoService implements IPricingService {
         return { ...cachedMap, ...missingTokenPrices };
     }
 
-    private formatTokenCacheKey(tokenId: string, currency: string) {
-        return `${tokenId}.${currency}`;
-    }
-
     /**
      * Retrieves multiple token prices from the cache at once.
      * @param keys - An array of cache keys.

libs/pricing/test/unit/services/coingecko.service.spec.ts

@@ -112,6 +112,34 @@ describe("CoingeckoService", () => {
             ]);
         });
 
+        it("fetches cached prices and missing from coingecko", async () => {
+            const tokenIds = ["token1", "token2"];
+            const expectedResponse: TokenPrices = {
+                token2: { usd: 4.56 },
+            };
+
+            jest.spyOn(cache.store, "mget").mockResolvedValueOnce([1.25, undefined]);
+            jest.spyOn(axios, "get").mockResolvedValueOnce({
+                data: expectedResponse,
+            });
+
+            const result = await service.getTokenPrices(tokenIds);
+
+            expect(result).toEqual({
+                token1: 1.25,
+                token2: 4.56,
+            });
+            expect(axios.get).toHaveBeenCalledWith(`simple/price`, {
+                params: {
+                    vs_currencies: BASE_CURRENCY,
+                    ids: "token2",
+                    precision: DECIMALS_PRECISION.toString(),
+                },
+            });
+            expect(cache.store.mget).toHaveBeenCalledWith("token1", "token2");
+            expect(cache.store.mset).toHaveBeenCalledWith([["token2", 4.56]]);
+        });
+
         it("throw ApiNotAvailable when Coingecko returns a 500 family exception", async () => {
             const tokenIds = ["token1", "token2"];