vitest.config.ts

import { coverageConfigDefaults, defineConfig } from 'vitest/config';

export default defineConfig({
  // Tests acquire their fixtures with `using`. Oxc downlevels `using` to a
  // helper from `@oxc-project/runtime` (not a dependency) unless the target
  // keeps it native; the test runner is the pinned dev Node, which supports
  // it. Only the test transform is affected; the library build has its own
  // config and its own, lower, target.
  oxc: { target: 'esnext' },
  test: {
    environment: 'jsdom',
    globals: true,
    // Test files are being migrated from .js to .ts; match both until the
    // migration completes. The playground page (see `demo/playground`) has
    // tests of its own; coverage below stays scoped to `src`, so demo code
    // never moves the thresholds.
    include: ['src/**/*.test.{js,ts}', 'demo/**/*.test.ts'],
    // Run the type level tests (`*.test-d.ts`) alongside the runtime ones.
    typecheck: { enabled: true },
    coverage: {
      provider: 'v8',
      include: ['src/**/*.{js,ts}'],
      // Type level tests hold no runtime code to cover, and the default
      // exclusions do not cover the `.test-d.` infix.
      exclude: [...coverageConfigDefaults.exclude, '**/*.test-d.{js,ts}'],
      thresholds: {
        statements: 95,
        branches: 90,
        functions: 95,
        lines: 95,
      },
    },
  },
});