From 5ddb12d43ce399e166e159be9faf364f9647c705 Mon Sep 17 00:00:00 2001
From: CJ42 <cavallerajean@gmail.com>
Date: Fri, 3 May 2024 00:32:02 +0100
Subject: [PATCH] feat: allow to use `decodeData` to decode Array length only

---
 src/lib/decodeData.test.ts | 21 +++++++++++++++++++++
 src/lib/decodeData.ts      | 17 +++++++++++------
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/src/lib/decodeData.test.ts b/src/lib/decodeData.test.ts
index f1e398ed..39545ebf 100644
--- a/src/lib/decodeData.test.ts
+++ b/src/lib/decodeData.test.ts
@@ -263,6 +263,27 @@ describe('decodeData', () => {
     ]);
   });
 
+  it('parses type Array correctly but just the array length', () => {
+    const decodedData = decodeData(
+      {
+        keyName: 'LSP12IssuedAssets[]',
+        value: '0x00000000000000000000000000000003',
+      },
+      [
+        {
+          name: 'LSP12IssuedAssets[]',
+          key: '0x7c8c3416d6cda87cd42c71ea1843df28ac4850354f988d55ee2eaa47b6dc05cd',
+          keyType: 'Array',
+          valueContent: 'Address',
+          valueType: 'address',
+        },
+      ],
+    );
+
+    expect(decodedData.name).to.eql('LSP12IssuedAssets[]');
+    expect(decodedData.value).to.eql(3);
+  });
+
   it('decodes dynamic keys', () => {
     const decodedData = decodeData(
       [
diff --git a/src/lib/decodeData.ts b/src/lib/decodeData.ts
index cecb0bf8..05050361 100644
--- a/src/lib/decodeData.ts
+++ b/src/lib/decodeData.ts
@@ -31,7 +31,7 @@ import {
 import { isDynamicKeyName } from './encodeKeyName';
 import { valueContentEncodingMap, decodeValueType } from './encoder';
 import { getSchemaElement } from './getSchemaElement';
-import { decodeKeyValue, encodeArrayKey } from './utils';
+import { countNumberOfBytes, decodeKeyValue, encodeArrayKey } from './utils';
 
 const tupleValueTypesRegex = /bytes(\d+)/;
 const valueContentsBytesRegex = /Bytes(\d+)/;
@@ -195,23 +195,28 @@ export function decodeKey(schema: ERC725JSONSchema, value) {
 
   switch (lowerCaseKeyType) {
     case 'array': {
-      const results: any[] = [];
-
       // If user has requested a key which does not exist in the contract, value will be: 0x and value.find() will fail.
-      if (!value || typeof value === 'string') {
-        return results;
+      if (!value) {
+        return [];
+      }
+
+      // Decode as a Number when when the encoded value is to set the Array length only
+      if (typeof value === 'string' && countNumberOfBytes(value) === 16) {
+        return decodeKeyValue('Number', 'uint128', value, schema.name) || 0;
       }
 
       const valueElement = value.find((e) => e.key === schema.key);
       // Handle empty/non-existent array
       if (!valueElement) {
-        return results;
+        return [];
       }
 
       const arrayLength =
         decodeKeyValue('Number', 'uint128', valueElement.value, schema.name) ||
         0;
 
+      const results: any[] = [];
+
       // This will not run if no match or arrayLength
       for (let index = 0; index < arrayLength; index++) {
         const dataElement = value.find(