vitest/docs/guide/coverage.md

title
Coverage | Guide

Coverage

Vitest supports Native code coverage via c8 and instrumented code coverage via istanbul.

Coverage Providers

:::tip Since Vitest v0.22.0 :::

Both c8 and istanbul support are optional. By default, c8 will be used.

You can select the coverage tool by setting test.coverage.provider to either c8 or istanbul:

// vite.config.ts
import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    coverage: {
      provider: 'istanbul' // or 'c8'
    },
  },
})

When you start the Vitest process, it will prompt you to install the corresponding support package automatically.

Or if you prefer to install them manually:

# For c8
npm i -D @vitest/coverage-c8

# For istanbul
npm i -D @vitest/coverage-istanbul

Coverage Setup

To test with coverage enabled, you can pass the --coverage flag in CLI.

{
  "scripts": {
    "test": "vitest",
    "coverage": "vitest run --coverage"
  }
}

To configure it, set test.coverage options in your config file:

// vite.config.ts
import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    coverage: {
      reporter: ['text', 'json', 'html'],
    },
  },
})

Custom Coverage Provider

It's also possible to provide your custom coverage provider by passing an object to the test.coverage.provider:

// vite.config.ts
import { defineConfig } from 'vitest/config'
import CustomCoverageProvider from 'my-custom-coverage-provider'

export default defineConfig({
  test: {
    coverage: {
      provider: CustomCoverageProvider()
    },
  },
})

Please refer to the type definition for more details.