What is vitest-code-coverage-report?

vitest-code-coverage-report is a modern, self-hosted viewer for the JSON coverage output produced by Vitest, Istanbul or V8.

Instead of digging through static HTML reports or paying for a cloud service, you can spin up a polished local dashboard with one command and explore your coverage with donuts, folder trees, file lists and a fully-featured source viewer.

Why?

The default html reporter is functional but dated. CI dashboards are great for trends but slow to navigate during a TDD loop. This package fills the gap with:

• Speed — runs as a tiny local Node server and a Vite-built SPA
• Clarity — Istanbul-parity per-line and per-branch overlays
• Focus — insights surface files that need attention first
• Privacy — your coverage data never leaves your machine

What you get

• Summary donuts for statements / branches / functions / lines
• Collapsible folder tree with aggregated metrics
• Sortable file list with filters
• Source drill-down with per-line hit/miss counts and branch markers
• Insights panel: coverage risk, quick wins, flaky-zone candidates
• Dark / light theme, persistent settings, keyboard shortcuts

How it works

1. Vitest (or any Istanbul/V8 instrumented runner) emits coverage/coverage-final.json.
2. code-coverage-report starts a local server that reads that JSON and serves the UI on http://127.0.0.1:5179.
3. The UI lazy-loads source files from disk so per-line overlays match your real source.

Coverage data never leaves your machine — everything runs locally.

Ready to try it? Head to Getting Started.