JavaScript debugger

Debugger for .js, .mjs, and .ts code running in the Graalium / GraalVM polyglot engine.

Protocol and port

The Graalium engine exposes a JDWP-style debug protocol. The browser debugger UI attaches to it over WebSocket.

• Default port 8081.
• Configurable via DIRIGIBLE_JAVASCRIPT_GRAALVM_DEBUGGER_PORT.
• Debugging is enabled by default (DIRIGIBLE_GRAALIUM_ENABLE_DEBUG=true).

UI

Set breakpoints by clicking the gutter glyph margin in the Monaco editor. Once attached, paused execution highlights the current line and populates the side panels:

• Call stack - stack frames; click a frame to switch the variables view to that scope.
• Variables - local and global variables, including closure scope when applicable. Expand objects to inspect properties.
• Watch - user-added expressions evaluated against the current frame.
• Breakpoints - all set breakpoints across files; toggle and remove.

Step controls: continue, step over, step into, step out.

See also

• Java debugger for client .java code.
• Monaco editor for setting and managing breakpoint glyphs.