devtools
- Type: object with the properties below
- Optional
- Experimental
Devtools integration options.
In the default 'full' mode, Rolldown writes JSON-lines devtools output under node_modules/.rolldown/{session_id}/, resolved against cwd. Consumers can parse the output with @rolldown/debug after await bundle.close() resolves.
sessionId replaces the generated session id. It must be one path segment: not empty, not . or .., and without /, \ or NUL. Rolldown does not check that it is unique: give each bundler that runs at the same time its own sessionId, or their devtools output mixes. The name unknown-session is reserved regardless of case.
In 'report' mode, Rolldown writes a small build report instead of the multi-GB logs.json: Markdown views, metrics.json with a build-over-build delta, module-graph.json, chunk-graph.json and history.jsonl. The report goes to node_modules/.rolldown/report/<output dir>, resolved against cwd, where <output dir> is the output folder relative to cwd (each .. becomes __). Rolldown writes it when the bundle closes. watch() and the dev engine write no report. See the Build Report guide for the files and how to compare builds.
mode?
- Type:
"full"|"report" - Optional
'full' (default): write JSON-lines devtools logs. 'report': write a small build report to node_modules/.rolldown/report/ instead. Any other value fails the build.
sessionId?
- Type:
string - Optional