Debugging with the ESM Build

This guide demonstrates how to rapidly develop/modify/test features within the VexFlow library. It is targeted at developers who wish to edit VexFlow source code (to customize its capability beyond what is offered, or to submit a PR to the main repo).

The process below requires VexFlow 4 or newer (since earlier versions did not include an ESM build).

Short Summary

1. Run grunt test:browser:esm from the vexflow/ directory. This will open http://127.0.0.1:8080/tests/flow.html?esm=true and also compile the ESM build in watch mode.
2. Navigate to the test you want by using the "Module:" dropdown and/or the "Filter:" search box.
3. Modify VexFlow. When you save a source file, the ESM build will be recompiled.
4. Refresh your webpage and see the results.