Function resolveCoverageProviderModule

packages/vitest/src/utils/coverage.ts:36–86

(
  options: SerializedCoverageConfig | undefined,
  loader: RuntimeCoverageModuleLoader,
)

}

export async function resolveCoverageProviderModule(
  options: SerializedCoverageConfig | undefined,
  loader: RuntimeCoverageModuleLoader,
): Promise<RuntimeCoverageProviderModule | null> {
  if (!options?.enabled || !options.provider) {
    return null
  }

  const provider = options.provider

  if (provider === 'v8' || provider === 'istanbul') {
    let builtInModule = CoverageProviderMap[provider]

    if (provider === 'v8' && loader.isBrowser) {
      builtInModule += '/browser'
    }

    const { default: coverageModule }
      = loader.isBrowser
        ? await loader.import(builtInModule)
        : await import(/* @vite-ignore */ builtInModule)

    if (!coverageModule) {
      throw new Error(
        `Failed to load ${CoverageProviderMap[provider]}. Default export is missing.`,
      )
    }

    return coverageModule
  }

  let customProviderModule

  try {
    customProviderModule = await loader.import(options.customProviderModule!)
  }
  catch (error) {
    throw new Error(
      `Failed to load custom CoverageProviderModule from ${options.customProviderModule}`,
      { cause: error },
    )
  }

  if (customProviderModule.default == null) {
    throw new Error(
      `Custom CoverageProviderModule loaded from ${options.customProviderModule} was not the default export`,
    )
  }

  return customProviderModule.default
}