@lexbuild/fr

Converts Federal Register XML into structured Markdown optimized for AI, RAG pipelines, and semantic search. Downloads documents via the FederalRegister.gov API with rich JSON metadata (agencies, CFR references, docket IDs, effective dates) alongside XML full text.

Tip: For command-line usage, install @lexbuild/cli instead. This package is the programmatic API.

Install

npm install @lexbuild/fr
# or
pnpm add @lexbuild/fr

Peer dependency: @lexbuild/core (installed automatically via workspace protocol in the monorepo).

Quick Start

Download and Convert

import { downloadFrDocuments, convertFrDocuments } from "@lexbuild/fr";

// Download last 30 days of Federal Register documents
const download = await downloadFrDocuments({
  output: "./downloads/fr",
  from: "2026-03-01",
  to: "2026-03-31",
});
console.log(`Downloaded ${download.documentsDownloaded} documents`);

// Convert to Markdown
const result = await convertFrDocuments({
  input: "./downloads/fr",
  output: "./output",
  linkStyle: "plaintext",
  dryRun: false,
});

console.log(`${result.documentsConverted} documents, ${result.totalTokenEstimate} est. tokens`);

Download by Document Type

import { downloadFrDocuments } from "@lexbuild/fr";

// Download only final rules from Q1 2026
const result = await downloadFrDocuments({
  output: "./downloads/fr",
  from: "2026-01-01",
  to: "2026-03-31",
  types: ["RULE"],
});

Download a Single Document

import { downloadSingleFrDocument } from "@lexbuild/fr";

const file = await downloadSingleFrDocument("2026-06029", "./downloads/fr");
console.log(`XML: ${file.xmlPath}`);
console.log(`JSON: ${file.jsonPath}`);

Convert with Type Filtering

import { convertFrDocuments } from "@lexbuild/fr";

const result = await convertFrDocuments({
  input: "./downloads/fr",
  output: "./output",
  linkStyle: "plaintext",
  dryRun: false,
  from: "2026-01-01",
  to: "2026-03-31",
  types: ["RULE", "PRORULE"], // Only rules and proposed rules
});

API Reference

Functions

Types

Classes

Constants

Output

Each document produces one Markdown file organized by publication date:

No granularity options — FR documents are already atomic (one file per document).

Frontmatter

FR documents include source-specific metadata alongside standard LexBuild fields. When a JSON sidecar from the API is available, frontmatter is enriched with structured agency, CFR reference, docket, and date information:

---
identifier: "/us/fr/2026-06029"
source: "fr"
legal_status: "authoritative_unofficial"
title: "Meeting of the Advisory Board on Radiation and Worker Health"
title_number: 0
title_name: "Federal Register"
section_number: "2026-06029"
positive_law: false
currency: "2026-03-30"
last_updated: "2026-03-30"
agency: "Health and Human Services Department"
document_number: "2026-06029"
document_type: "notice"
fr_citation: "91 FR 15619"
fr_volume: 91
publication_date: "2026-03-30"
agencies:
  - "Health and Human Services Department"
  - "Centers for Disease Control and Prevention"
fr_action: "Notice of meeting."
---

Rules and proposed rules include additional fields:

cfr_references:
  - "10 CFR Part 53"
  - "10 CFR Part 50"
docket_ids:
  - "NRC-2019-0062"
rin: "3150-AK31"
effective_date: "2026-04-29"

Data Source

The downloader fetches both JSON metadata (40+ structured fields) and XML full text per document. Large date ranges are automatically chunked by month to stay under the API's 10,000-result cap per query.

Document Types

Compatibility

• Node.js >= 22
• ESM only — no CommonJS build
• TypeScript — ships .d.ts type declarations

Monorepo Context

Part of the LexBuild monorepo. Depends on @lexbuild/core for XML parsing, AST types, and Markdown rendering.

pnpm turbo build --filter=@lexbuild/fr
pnpm turbo test --filter=@lexbuild/fr

Related Packages

License

MIT