fix(ui): add support for ui coverage with subdir option

docs/guide/coverage.md

@@ -169,7 +169,9 @@ To see all configurable options for coverage, see the [coverage Config Reference
 
 Since Vitest 0.31.0, you can check your coverage report in [Vitest UI](./ui).
 
-If you have configured coverage reporters, don't forget to add `html` reporter to the list, Vitest UI will only enable html coverage report if it is present.
+Vitest UI will enable coverage report when it is enabled explicitly and the html coverage reporter is present, otherwise it will not be available:
+- enable `coverage.enabled=true` in your configuration or run Vitest with `--coverage.enabled=true` flag
+- add `html` to the `coverage.reporters` list: you can also enable `subdir` option to put coverage report in a subdirectory
 
 <img alt="html coverage activation in Vitest UI" img-light src="/vitest-ui-show-coverage-light.png">
 <img alt="html coverage activation in Vitest UI" img-dark src="/vitest-ui-show-coverage-dark.png">

packages/ui/client/composables/navigation.ts

@@ -21,7 +21,15 @@ export const coverageUrl = computed(() => {
   if (coverageEnabled.value) {
     const url = `${window.location.protocol}//${window.location.hostname}:${config.value!.api!.port!}`
     const idx = coverage.value!.reportsDirectory.lastIndexOf('/')
-    return `${url}/${coverage.value!.reportsDirectory.slice(idx + 1)}/index.html`
+    const htmlReporter = coverage.value!.reporter.find((reporter) => {
+      if (reporter[0] !== 'html')
+        return undefined
+
+      return reporter
+    })
+    return htmlReporter && 'subdir' in htmlReporter[1]
+      ? `${url}/${coverage.value!.reportsDirectory.slice(idx + 1)}/${htmlReporter[1].subdir}/index.html`
+      : `${url}/${coverage.value!.reportsDirectory.slice(idx + 1)}/index.html`
   }
 
   return undefined

packages/ui/node/index.ts

@@ -13,11 +13,11 @@ export default (ctx: Vitest) => {
       const uiOptions = ctx.config
       const base = uiOptions.uiBase
       const coverageFolder = resolveCoverageFolder(ctx)
-      const coveragePath = coverageFolder ? `/${basename(coverageFolder)}/` : undefined
+      const coveragePath = coverageFolder ? coverageFolder[1] : undefined
       if (coveragePath && base === coveragePath)
         throw new Error(`The ui base path and the coverage path cannot be the same: ${base}, change coverage.reportsDirectory`)
 
-      coverageFolder && server.middlewares.use(coveragePath!, sirv(coverageFolder, {
+      coverageFolder && server.middlewares.use(coveragePath!, sirv(coverageFolder[0], {
         single: true,
         dev: true,
         setHeaders: (res) => {
@@ -35,20 +35,30 @@ export default (ctx: Vitest) => {
 
 function resolveCoverageFolder(ctx: Vitest) {
   const options = ctx.config
-  const enabled = options.api?.port
-    && options.coverage?.enabled
-    && options.coverage.reporter.some((reporter) => {
+  const htmlReporter = (options.api?.port && options.coverage?.enabled)
+    ? options.coverage.reporter.find((reporter) => {
       if (typeof reporter === 'string')
         return reporter === 'html'
 
-      return reporter.length && reporter.includes('html')
+      return reporter[0] === 'html'
     })
+    : undefined
+
+  if (!htmlReporter)
+    return undefined
 
   // reportsDirectory not resolved yet
-  return enabled
-    ? resolve(
-      ctx.config?.root || options.root || process.cwd(),
-      options.coverage.reportsDirectory || coverageConfigDefaults.reportsDirectory,
-    )
+  const root = resolve(
+    ctx.config?.root || options.root || process.cwd(),
+    options.coverage.reportsDirectory || coverageConfigDefaults.reportsDirectory,
+  )
+
+  const subdir = (Array.isArray(htmlReporter) && htmlReporter.length > 1 && 'subdir' in htmlReporter[1])
+    ? htmlReporter[1].subdir
     : undefined
+
+  if (!subdir)
+    return [root, `/${basename(root)}/`]
+
+  return [resolve(root, subdir), `/${basename(root)}/${subdir}/`]
 }