fix: bytes field should be typed as a Buffer (#1652)

Co-authored-by: sofisl <[email protected]>

Author: alvarowolfx

tools/src/compileProtos.ts

@@ -147,8 +147,9 @@ function updateDtsTypes(dts: string, enums: Set<string>): string {
         `${typeName}|keyof typeof ${typeName}`
       );
     } else if (typeName === 'Uint8Array') {
-      // bytes: Uint8Array => Uint8Array|string to allow base64-encoded strings
-      replaced = replaced.replace(typeName, `${typeName}|string`);
+      // bytes: Uint8Array => Uint8Array|Buffer|string to allow base64-encoded strings
+      // and byte field can also come as a Buffer when pbjs uses $util.newBuffer.
+      replaced = replaced.replace(typeName, `${typeName}|Buffer|string`);
     } else if (typeName === 'Long') {
       // Longs can be passed as strings :(
       // number|Long => number|Long|string

tools/test/compileProtos.ts

@@ -242,7 +242,9 @@ describe('compileProtos tool', () => {
       ts.toString().includes('http://www.apache.org/licenses/LICENSE-2.0')
     );
     assert(ts.toString().includes('longField?: (number|Long|string|null);'));
-    assert(ts.toString().includes('bytesField?: (Uint8Array|string|null);'));
+    assert(
+      ts.toString().includes('bytesField?: (Uint8Array|Buffer|string|null);')
+    );
     assert(
       ts
         .toString()
@@ -258,7 +260,9 @@ describe('compileProtos tool', () => {
         )
     );
     assert(ts.toString().includes('public longField: (number|Long|string);'));
-    assert(ts.toString().includes('public bytesField: (Uint8Array|string);'));
+    assert(
+      ts.toString().includes('public bytesField: (Uint8Array|Buffer|string);')
+    );
     assert(
       ts
         .toString()