Quick Start

Run the analyzer

From your project root:

npx vitest-dedup .

Discovery reads your Vitest configuration statically — test.include, test.exclude, test.globals, project lists, and the typecheck channel — then every matched test file is parsed and compared. Nothing is imported or executed.

vitest-dedup check <path> is the explicit form of vitest-dedup <path>.

Read the output

The terminal report groups findings by rule. Each finding shows its severity and message, a --> primary location and related: locations, and a rule-specific action: line naming the remedy. The footer summarizes analyzed tests and files, severities, inline suppressions, and the error-level duplication threshold.

With the default threshold of 0, any error-severity finding fails the run — see exit codes.

Act on findings

The remedy depends on the verdict:

• Redundant — one copy can go. Review removal, or repair the coverage one of the copies was supposed to provide.
• Consolidatable — every case is needed; they belong in one test.each table. Deleting a row would lose coverage.
• Name collision — rename one of the tests.
• Similar, review decides — the tests look equivalent without establishing that either adds no coverage. Review, and if they are the same behavior, consolidate.

A finding that is not debt — a deliberately parallel pair, for example — can be answered next to the code instead of in a baseline file:

// vitest-dedup-disable-next-line these two are deliberately parallel examples
test('adds numbers', () => {
  expect(add(1, 1)).toBe(2);
});

Every report states how many findings were suppressed this way.

Adopting on an existing codebase

A codebase with existing duplication cannot turn the gate on at once. Record what is there, then gate on what is added:

vitest-dedup . --baseline dedup-baseline.json --update-baseline   # record today's findings
vitest-dedup . --baseline dedup-baseline.json                     # gate only on what is new

See CI Integration for the full adoption path.

Next steps

• Browse every flag in the CLI reference.
• Tune severities in configuration.
• Choose a report format for how you read results.