Test Strategy#

The suite protects the package's actual product boundary: valid code commonly published in blogs and documentation, with a small browser payload and synchronous client performance.

Contracts#

• Every supported language has committed code from real TanStack Markdown or MDX files.
• The corpus contains up to twenty samples per language and currently totals 333 blocks.
• Every token stream reconstructs its source byte for byte.
• Focused regressions cover context-sensitive failures such as TSX generics, nested template interpolation, regular expressions, Python triple strings, shell heredocs, YAML fragments and block scalars, and markup embeddings.
• HTML uses one escaped <pre><code> tree with no inline style attributes.
• Unknown languages fall back to plaintext.
• Remark and rehype produce structured nodes and do not require raw HTML.
• Every public ESM subpath imports directly from the packed package shape.

Size Profiles#

pnpm run size builds five browser profiles independently. Each has minified, gzip, and Brotli budgets:

The selective profiles are the primary product metric. The all-language profile protects the convenience entry from unbounded growth.

Throughput#

pnpm run bench processes at least 10,000 blocks from the committed real-doc corpus. The 1.2 second CI budget is based on the shared-runner baseline and still catches structural regressions.

pnpm run compare:sugar-high compares the overlapping JS/TS/JSX/TSX use case. pnpm run compare:shiki compares all supported fixtures. These are directional measurements, not claims of equivalent grammar depth.

Deliberate Omissions#

The package does not maintain compiler conformance suites, malformed-input fuzzing, ReDoS corpora, editor state tests, or exact parity snapshots against another highlighter. Those would optimize for a broader parser product than this library intends to become.