feat(projection): ignore burn transactions when projecting cip25 metadata

cardano-foundation/CIPs#527

Author: mkazlauskas

packages/projection/src/operators/Mappers/withNftMetadata.ts

@@ -30,7 +30,8 @@ const getNftMetadataFromCip67 = ({ cip67 }: WithCIP67, logger: Logger) =>
   );
 
 const getNftMetadataFromCip25 = ({ mint }: WithMint, logger: Logger) =>
-  mint.map(({ assetId, txMetadata, policyId, assetName }): ProjectedNftMetadata | null => {
+  mint.map(({ assetId, txMetadata, policyId, assetName, quantity }): ProjectedNftMetadata | null => {
+    if (quantity < 1n) return null;
     const nftMetadata = Asset.NftMetadata.fromMetadatum({ name: assetName, policyId }, txMetadata, logger);
 
     if (!nftMetadata) return null;

packages/projection/test/operators/Mappers/withNftMetadata.test.ts

@@ -53,6 +53,7 @@ const datumNftmetadata = {
 describe('withNftMetadata', () => {
   const assetId1 = Cardano.AssetId('7d878696b149b529807aa01b8e20785e0a0d470c32c13f53f08a55e344455630303032');
   const assetId2 = Cardano.AssetId('7d878696b149b529807aa01b8e20785e0a0d470c32c13f53f08a55e344455638393230');
+  const assetId3 = Cardano.AssetId('7d878696b149b529807aa01b8e20785e0a0d470c32c13f53f08a55e344455638393233');
   const otherProperties1 = new Map([
     ['Background', 'Ocean'],
     ['Body', 'Pale'],
@@ -97,6 +98,14 @@ describe('withNftMetadata', () => {
                   ['name', 'DEV 0002']
                 ])
               ],
+              [
+                Buffer.from(Cardano.AssetId.getAssetName(assetId3), 'hex').toString('utf8'),
+                new Map([
+                  ['image', 'ipfs://QmWmB37VZ9uc2cVe2fG31Xqjxw5VbUu4DMLkGt9LW6z7Up'],
+                  ['mediaType', 'image/jpeg'],
+                  ['name', 'Burned']
+                ])
+              ],
               [
                 'DEV8920',
                 new Map([
@@ -121,7 +130,8 @@ describe('withNftMetadata', () => {
           body: {
             mint: new Map([
               [assetId1, 1n],
-              [assetId2, 1n]
+              [assetId2, 1n],
+              [assetId3, -1n]
             ])
           }
         }