ThumbImage not applied when using compiled JS, works with TS source

[pingkai]

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Description:
When using the compiled JS version of @react-native-community/slider, the thumbImage prop does not get applied on iOS, even when provided. Using the TS source code directly works as expected.

Steps to reproduce:
1. Use the JS build of the slider in a React Native project on iOS.
2. Pass thumbImage={require('transparent.png')}.
3. Observe that the thumb image is not set, and the setter in native code is never called.
4. Replace the JS import with the TS source code. The thumb image is applied correctly.

Expected behaviour:
thumbImage should work correctly in the JS build, just like the TS source.

Environment:
• React Native: [0.79.6]
• @react-native-community/slider: 5.0.1
• iOS: 26.0

Notes:
• The problem seems related to the build/compilation logic in the JS bundle, possibly the way conditional assignment is optimized.
• Using TS source bypasses the issue.

Today I used patch-package to patch @react-native-community/slider@5.0.1 for the project I'm working on.

Here is the diff that solved my problem:

diff --git a/node_modules/@react-native-community/slider/package.json b/node_modules/@react-native-community/slider/package.json
index 19bd73b..3f34810 100644
--- a/node_modules/@react-native-community/slider/package.json
+++ b/node_modules/@react-native-community/slider/package.json
@@ -8,8 +8,7 @@
   "publishConfig": {
     "access": "public"
   },
-  "main": "dist/Slider.js",
-  "types": "typings/index.d.ts",
+  "main": "src/Slider.tsx",
   "keywords": [
     "react-native",
     "react native",

This issue body was partially generated by patch-package.

[BartoszKlonowski]

Hello @pingkai, thank you for the kind words :)
Yes, this is a known issue that is originally reported in #711. Although it sounds differently, the case is exactly the same - thumbImage not being loaded correctly, and, judging briefly by your investigation (thank you!) the root cause is what I initially assumed to be when implemented the fixing PR. However, as you may notice when will check this - the approach I took was from the native side manipulating with what codegen misses to generate regarding the types for the image.
But, considering your input here I will take a closer look and adjust the solution before merging the fix.

For the time being let me, please, close this issue as a duplicate of #711, but thanks again for reaching out and providing your findings, that is mega appreciated 🙏