chore: change order of code to be clearer

packages/instant/src/types.ts

@@ -41,6 +41,7 @@ export interface ERC721Asset {
     assetData: string;
     metaData: ERC721AssetMetaData;
 }
+
 export interface Asset {
     assetData: string;
     metaData: AssetMetaData;

packages/instant/src/util/asset.ts

@@ -16,10 +16,11 @@ export const assetUtils = {
         };
     },
     getMetaDataOrThrow: (assetData: string, metaDataMap: ObjectMap<AssetMetaData>, network: Network): AssetMetaData => {
-        let mainnetAssetData: string | undefined = assetData;
+        let mainnetAssetData: string | undefined;
         if (network !== Network.Mainnet) {
             mainnetAssetData = assetUtils.getAssociatedAssetDataIfExists(assetData, network);
         }
+        mainnetAssetData = assetData;
         if (_.isUndefined(mainnetAssetData)) {
             throw new Error(ZeroExInstantError.AssetMetaDataNotAvailable);
         }