Reports

Choose a reporter by how the result will be consumed.

Reporter	Destination	Best for
terminal	stdout	Interactive use and readable CI logs.
jsonl	stdout	Streaming shell pipelines and AI agent workflows.
json	File	Structured integrations and complete run metadata.
html	File	Searchable human review with light and dark themes and per-finding source snippets.
sarif	File	GitHub code scanning and other SARIF 2.1.0 consumers.

vitest-dedup .                                             # terminal
vitest-dedup . --reporters json,html --output reports/vd   # files only
vitest-dedup . --reporters sarif --output reports/vd       # for upload-sarif
vitest-dedup . --reporters jsonl | jq -c 'select(.type == "finding")'

terminal and jsonl both own stdout and cannot be selected together. jsonl combines freely with the file reporters, which never touch stdout.

Writing files

--output is a filename stem, not a directory: --output reports/vd writes reports/vd.json. Without --output, file reporters use the stem reports/vitest-dedup. Parent directories are created as needed.

• Each report is buffered into a temporary file in its output directory, then atomically replaces the destination after successful serialization and flush.
• A final-component symlink is replaced without writing to its target.
• If writing fails, the previous report remains intact and the run fails.
• Several selected reports are replaced independently.

After every selected file report has been written successfully, file-only runs print Reports written to: followed by indented, sanitized paths.

Diagnostics

Diagnostics stay on stderr: early operational errors, globals detection, incomplete coverage, baseline and changed-file qualifications, and the opt-in cell census. Lists are bounded with explicit omission counts — at most 20 immediate read failures, 20 deferred diagnostic messages, 10 wholly excluded files, and 10 files containing only statically empty tables. Counts describe all affected messages and files; display limits do not change analyzed scope, findings, or exit policy.

Safety and determinism

Report content is data: every reporter sanitizes it. The same admitted input produces byte-identical output, with two exceptions — terminal output includes the detection time unless --no-metrics is set, and the --debug-memory record carries process-dependent figures such as peak RSS.