@accesslint/report

Generate trend reports from @accesslint/jest, @accesslint/vitest, and @accesslint/playwright snapshot history.

Those packages append one NDJSON record to accessibility-snapshots/.history.ndjson every time a baseline is created, ratcheted down, or force-updated. This tool reads that sidecar and emits a report showing how violations have trended over time.

Usage

# Markdown (default) — good for PR comments
npx @accesslint/report > a11y-report.md

# Single-file HTML with an SVG chart per snapshot
npx @accesslint/report --format html --out a11y-report.html

# Raw JSON for downstream tooling
npx @accesslint/report --format json

# Filter to a single snapshot
npx @accesslint/report --snapshot login-form

# Point at a non-default directory
npx @accesslint/report --dir ./test/a11y-snapshots

What's in the report

• Summary — totals for events, snapshots, added/removed violations, and the observed window.
• Per-snapshot timeline — an event log plus a stacked-area chart (HTML only) of total violations over time.
• Rule movement — which rules appeared and were fixed across the history, joined to WCAG level + criterion from @accesslint/core.

Limits

• The sidecar only records events from runs that wrote the snapshot file (created / ratchet / force-update). Passing runs that matched the baseline leave no trace — they're visible in your CI logs, not here.
• Events are classified by what the matcher saw, not by git intent. A force-update that adds violations means someone ran with ACCESSLINT_UPDATE=1 or -u; the report surfaces that so regressions don't disappear silently.
• Rule metadata lookups against @accesslint/core only succeed for built-in rules. Custom rules passed via additionalRules show up as level: "unknown" with empty WCAG.

Programmatic API

import { loadAllHistory, aggregate, emitMarkdown } from "@accesslint/report";

const records = loadAllHistory("./accessibility-snapshots");
const report = aggregate(records);
console.log(emitMarkdown(report));

License

MIT