fix: encode empty Uint8Array as NULL for BYTEA parameters (#146)

* fix: encode empty Uint8Array as NULL for BYTEA parameters

Problem:
When calling view actions with optional BYTEA parameters, there was no
way to pass SQL NULL from JavaScript. Passing JavaScript `null` resulted
in VarType.NULL (generic null), which didn't work correctly with SQL
`IS NULL` checks for BYTEA columns.

Root Cause:
In kwilEncoding.ts, empty Uint8Array(0) was always encoded as "not null
empty bytea" using encodeNotNull(), which produces '\x' in PostgreSQL.
This is semantically different from NULL and causes SQL `IS NULL` checks
to fail.

Solution:
Treat empty Uint8Array(0) as BYTEA NULL by encoding it with encodeNull()
instead of encodeNotNull(). This provides a JavaScript-idiomatic way to
represent BYTEA NULL while maintaining backward compatibility.

Changes:
- src/utils/kwilEncoding.ts (encodeValue function):
  * Add length check for Uint8Array before encoding
  * Empty Uint8Array (length === 0) → encodeNull()
  * Non-empty Uint8Array (length > 0) → encodeNotNull(value)

resolves: #145

* chore: apply suggestion

* chore: apply suggestion

* chore: bump version

Author: MicBun

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@trufnetwork/kwil-js",
-  "version": "0.9.9",
+  "version": "0.9.10",
   "description": "",
   "main": "./dist/index.js",
   "module": "./dist-esm/index.mjs",

src/utils/kwilEncoding.ts

@@ -220,6 +220,11 @@ export function encodeValue(value: ValueType, o?: VarType): Uint8Array {
 
   // handle Uint8Array case
   if (value instanceof Uint8Array) {
+    // Treat empty Uint8Array as NULL for BYTEA type
+    // This allows JavaScript code to pass new Uint8Array(0) to represent BYTEA NULL
+    if (value.length === 0) {
+      return encodeNull();
+    }
     return encodeNotNull(value);
   }
 
@@ -263,8 +268,14 @@ function overrideValue(v: ValueType, o: VarType): Uint8Array {
       return encodeNotNull(stringToBytes(v.toString()));
     case VarType.UUID:
       return encodeNotNull(convertUuidToBytes(v as string));
-    case VarType.BYTEA:
-      return encodeNotNull(v as Uint8Array);
+    case VarType.BYTEA: {
+      // Treat empty Uint8Array as NULL for consistency with normal encoding path
+      const byteaValue = v as Uint8Array;
+      if (byteaValue.length === 0) {
+        return encodeNull();
+      }
+      return encodeNotNull(byteaValue);
+    }
     default:
       throw new Error('invalid scalar value');
   }