Watching Non-Imported Files

In watch mode, Vitest tracks the import graph: when you change a file, every test whose imports reach that file reruns. That covers most cases. It misses tests that depend on files they don't import, like email templates loaded with fs.readFile, JSON fixtures parsed at runtime, HTML or CSS pulled in by a build step, or generated artifacts the tests assert against. Editing one of those files leaves the related tests stale, and the watch loop has no way to know.

watchTriggerPatterns 3.2.0+ makes these dependencies explicit. You declare a regex over file paths and a callback that returns which tests to rerun when a matching file changes.

Pattern

vitest.config.ts

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    watchTriggerPatterns: [
      {
        pattern: /src\/templates\/(.*)\.(ts|html|txt)$/,
        testsToRun: (file, match) => {
          // edit `src/templates/welcome.html` ⇒ rerun `api/tests/mailers/welcome.test.ts`
          return `api/tests/mailers/${match[1]}.test.ts`
        },
      },
    ],
  },
})

testsToRun returns one or more test file paths to rerun (as a string or string array), or undefined if no tests should rerun. Paths are resolved against the workspace root and are not interpreted as globs. match is the result of RegExp.exec against the changed file.

Variations

Multiple patterns can coexist. The first below derives the test path from the directory of the changed file; the second maps a single shared fixture to a fixed list of test files:

vitest.config.ts

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    watchTriggerPatterns: [
      {
        pattern: /src\/(.*)\/schema\.json$/,
        testsToRun: (_file, match) => `src/${match[1]}/__tests__/index.test.ts`,
      },
      {
        pattern: /test\/shared-fixture\.json$/,
        testsToRun: () => [
          'test/integration/users.test.ts',
          'test/integration/billing.test.ts',
        ],
      },
    ],
  },
})

forceRerunTriggers covers the same general gap, except it reruns every test on every match. watchTriggerPatterns reruns only the tests you map for a given pattern, which keeps the watch loop fast.

See also

• watchTriggerPatterns
• forceRerunTriggers