Fix empty asset data parsing

Author: cbovis

src/util/parse-asset-data.js

@@ -75,8 +75,26 @@ const extractERC1155Assets = assetData => {
   }));
 };
 
-const parseAssetData = (encodedData, amount) => {
+/**
+ * Determine whether encoded asset data is empty.
+ * @param {string} encodedData
+ */
+const isEmptyData = encodedData => {
   if (encodedData === '0x') {
+    return true;
+  }
+
+  if (!encodedData.startsWith('0x')) {
+    return false;
+  }
+
+  const valuesAfterX = encodedData.substr(2);
+
+  return valuesAfterX === '0'.repeat(valuesAfterX.length);
+};
+
+const parseAssetData = (encodedData, amount) => {
+  if (isEmptyData(encodedData)) {
     return [];
   }
 

src/util/parse-asset-data.test.js

@@ -0,0 +1,27 @@
+const parseAssetData = require('./parse-asset-data');
+
+describe('utils/parseAssetData', () => {
+  it('should return empty array when asset data is 0x', () => {
+    const assets = parseAssetData('0x', 0);
+
+    expect(assets).toEqual([]);
+  });
+
+  it('should return empty array when asset data is 0x0', () => {
+    const assets = parseAssetData('0x0', 0);
+
+    expect(assets).toEqual([]);
+  });
+
+  it('should return empty array when asset data is 0x00000', () => {
+    const assets = parseAssetData('0x00000', 0);
+
+    expect(assets).toEqual([]);
+  });
+
+  it('should return empty array when asset data is 0x0000000000', () => {
+    const assets = parseAssetData('0x0000000000', 0);
+
+    expect(assets).toEqual([]);
+  });
+});