From db886919d61d7558d5e143dbc2ef0e9520ac3ffa Mon Sep 17 00:00:00 2001
From: Navpreet Singh <ns.2004@outlook.com>
Date: Fri, 9 Oct 2026 23:23:41 +0100
Subject: [PATCH] fix(stream-transform): preserve objects with a non-callable
 then field

---
 packages/stream-transform/lib/index.js          |  2 +-
 packages/stream-transform/test/handler.types.js | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/stream-transform/lib/index.js b/packages/stream-transform/lib/index.js
index 07e31c129..266271cab 100644
--- a/packages/stream-transform/lib/index.js
+++ b/packages/stream-transform/lib/index.js
@@ -49,7 +49,7 @@ Transformer.prototype._transform = function (chunk, _, cb) {
     if (l === 1) {
       // sync
       const result = this.handler.call(this, chunk, this.options.params);
-      if (result && result.then) {
+      if (result && typeof result.then === "function") {
         result.then(
           (result) => {
             this.__done(null, [result], cb);
diff --git a/packages/stream-transform/test/handler.types.js b/packages/stream-transform/test/handler.types.js
index 8f3d696b3..a80bf1ef7 100644
--- a/packages/stream-transform/test/handler.types.js
+++ b/packages/stream-transform/test/handler.types.js
@@ -40,7 +40,7 @@ describe("handler.types", function () {
     );
   });
 
-  it("receive string and return object", function (next) {
+  it("receive string and return object with a then field", function (next) {
     transform(
       ["20322-051544", "28392-898392", "83929-843999"],
       (record) => {
@@ -48,16 +48,16 @@ describe("handler.types", function () {
         const [value_1, value_2] = record.split("-");
         record = {
           FIELD_1: value_1,
-          FIELD_2: value_2,
+          then: value_2,
         };
         return record;
       },
       (err, data) => {
         if (err) return next(err);
         data.should.eql([
-          { FIELD_1: "20322", FIELD_2: "051544" },
-          { FIELD_1: "28392", FIELD_2: "898392" },
-          { FIELD_1: "83929", FIELD_2: "843999" },
+          { FIELD_1: "20322", then: "051544" },
+          { FIELD_1: "28392", then: "898392" },
+          { FIELD_1: "83929", then: "843999" },
         ]);
         next();
       },