An error occurred while executing Hermes command... Vega 0.21 & 0.22

Vega Open Beta Bug Reports
4

Hi @Tony

Thank you for the detailed bug report on the Hermes compilation error.

I’m glad to hear the issue resolved itself after creating a build on the Vega Virtual Device. This suggests there may have been a cached or corrupted intermediate build artifact that was cleared during the simulator build process.

For future reference, if you encounter similar Hermes compilation errors, here are some troubleshooting steps that may help:

  1. Clean the build directory: Remove the build/ folder and rebuild
  2. Clear Metro bundler cache: npm start – --reset-cache
  3. Verify node_modules integrity: Delete node_modules/ and reinstall dependencies
  4. Build on the simulator first: As you discovered, this can help clear stale artifacts

The error message you encountered (‘;’ expected undefinedif (msg instanceof UpdateExperiment_1)) suggests the bundler may have generated malformed JavaScript, which could indicate a transient issue with the build pipeline or cached state.

Feel free to reach back to me if you have any questions or run into any issues!

Thanks for helping us improve the Vega platform.

Warm regards,
Aishwarya