epubcheck-ts
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    epubcheck-ts

    epubcheck-ts

    Validate EPUB files in Node.js and the browser. A TypeScript implementation of EPUBCheck.

    CI npm License

    Status: 93% feature parity with Java EPUBCheck (1061 tests passing, 74 skipped). See PROJECT_STATUS.md for details. For full EPUB 3 conformance testing, use the official Java EPUBCheck.

    • CLI and API — Use as a CLI tool (npx @likecoin/epubcheck-ts book.epub) or import as a library
    • Browser support — Works in Node.js 18+ and modern browsers via pure JS + WASM
    • No native dependencies — No Java, no compilation — npm install and go
    • TypeScript — Full type definitions included
    • Tree-shakable — ESM with proper exports for minimal bundle impact

    Live demo at likecoin.github.io/epubcheck-ts — validate EPUB files in the browser without uploading to any server.

    npm install @likecoin/epubcheck-ts

    Quick validation:

    npx @likecoin/epubcheck-ts book.epub

    Or install globally:

    npm install -g @likecoin/epubcheck-ts
    epubcheck-ts book.epub

    CLI Options:

    epubcheck-ts <file.epub> [options]

    Options:
      -j, --json <file>        Output JSON report to file (use '-' for stdout)
      -q, --quiet              Suppress console output (errors only)
      -p, --profile <name>     Validation profile (default|dict|edupub|idx|preview)
      -u, --usage              Include usage messages (best practices)
      -f, --fatal              Show only fatal errors
      -e, --error              Show fatal errors and errors
          --warn               Show fatal errors, errors, and warnings
      -c, --customMessages <file>  Override message severities (TSV: ID<tab>SEVERITY)
      -w, --fail-on-warnings   Exit with code 1 if warnings are found
      -l, --listChecks         List all message IDs and severities
      -v, --version            Show version information
      -h, --help               Show this help message

    Examples:

    # Basic validation
    epubcheck-ts book.epub

    # Generate JSON report
    epubcheck-ts book.epub --json report.json

    # Quiet mode for CI/CD
    epubcheck-ts book.epub --quiet --fail-on-warnings

    # Validate with specific profile
    epubcheck-ts dictionary.epub --profile dict

    # Show only errors (hide warnings/info)
    epubcheck-ts book.epub --error

    # Enable suppressed accessibility checks
    printf "ACC-004\tWARNING\nACC-005\tWARNING\n" > overrides.txt
    epubcheck-ts book.epub -c overrides.txt

    import { EpubCheck } from '@likecoin/epubcheck-ts';
    import { readFile } from 'node:fs/promises';

    // Load EPUB file
    const epubData = await readFile('book.epub');

    // Validate
    const result = await EpubCheck.validate(epubData);

    if (result.valid) {
      console.log('EPUB is valid!');
    } else {
      console.log(`Found ${result.errorCount} errors and ${result.warningCount} warnings`);
      
      for (const message of result.messages) {
        console.log(`${message.severity}: ${message.message}`);
        if (message.location) {
          console.log(`  at ${message.location.path}:${message.location.line}`);
        }
      }
    }

    const fs = require('node:fs');

    async function validate() {
      const { EpubCheck } = await import('epubcheck-ts');
      
      const epubData = fs.readFileSync('book.epub');
      const result = await EpubCheck.validate(epubData);
      
      console.log(result.valid ? 'Valid!' : 'Invalid');
    }

    validate();

    import { EpubCheck } from '@likecoin/epubcheck-ts';

    // From file input
    const fileInput = document.querySelector('input[type="file"]');
    fileInput.addEventListener('change', async (event) => {
      const file = event.target.files[0];
      const data = new Uint8Array(await file.arrayBuffer());
      
      const result = await EpubCheck.validate(data);
      console.log(result);
    });

    Full API reference: online | markdown

    EpubCheck.validate(data, options?)

    Static method to validate an EPUB file.

    Parameters:

    • data: Uint8Array - The EPUB file contents
    • options?: EpubCheckOptions - Optional validation options

    Returns: Promise<EpubCheckResult>

    new EpubCheck(options?)

    Create a reusable validator instance.

    const checker = new EpubCheck({
      version: '3.3',
      profile: 'default',
      locale: 'en',
    });

    const result1 = await checker.check(epub1Data);
    const result2 = await checker.check(epub2Data);

    interface EpubCheckOptions {
      /** EPUB version to validate against (auto-detected if not specified) */
      version?: '2.0' | '3.0' | '3.1' | '3.2' | '3.3';
      
      /** Validation profile */
      profile?: 'default' | 'edupub' | 'idx' | 'dict' | 'preview';
      
      /** Include usage messages in results (default: false) */
      includeUsage?: boolean;
      
      /** Include info messages in results (default: true) */
      includeInfo?: boolean;
      
      /** Maximum errors before stopping, 0 = unlimited (default: 0) */
      maxErrors?: number;
      
      /** Locale for messages (default: 'en') */
      locale?: string;
      
      /** Custom message severity overrides (message ID → severity) */
      customMessages?: Map<string, MessageSeverity>;
    }

    interface EpubCheckResult {
      /** Whether the EPUB is valid (no errors or fatal errors) */
      valid: boolean;
      
      /** All validation messages */
      messages: ValidationMessage[];
      
      /** Counts by severity */
      fatalCount: number;
      errorCount: number;
      warningCount: number;
      infoCount: number;
      usageCount: number;
      
      /** Detected EPUB version */
      version?: string;
      
      /** Validation time in milliseconds */
      elapsedMs: number;
    }

    interface ValidationMessage {
      /** Unique message identifier (e.g., 'OPF-001') */
      id: string;
      
      /** Severity level */
      severity: 'fatal' | 'error' | 'warning' | 'info' | 'usage';
      
      /** Human-readable message */
      message: string;
      
      /** Location in the EPUB */
      location?: {
        path: string;
        line?: number;
        column?: number;
        context?: string;
      };
      
      /** Suggestion for fixing the issue */
      suggestion?: string;
    }

    Generate a JSON report compatible with the original EPUBCheck:

    import { EpubCheck, Report } from '@likecoin/epubcheck-ts';

    const result = await EpubCheck.validate(data);
    const jsonReport = Report.toJSON(result);
    console.log(jsonReport);
    Environment Version Notes
    Node.js 18+ Full support
    Chrome 89+ Full support
    Firefox 89+ Full support
    Safari 15+ Full support
    Edge 89+ Full support

    This library is a TypeScript port of the Java-based EPUBCheck tool maintained by the W3C. Key implementation details:

    • XML Processing: Uses libxml2-wasm for XML parsing and schema validation (RelaxNG, XSD) via WebAssembly
    • ZIP Handling: Uses fflate for fast, lightweight EPUB container processing
    • CSS Validation: Uses css-tree for CSS parsing and validation
    • Schematron: Uses fontoxpath with slimdom for XPath 3.1 evaluation
    Component Status Completeness Notes
    OCF Container 🟢 Complete ~92% ZIP structure, mimetype, container.xml, encryption.xml obfuscation
    Package Document (OPF) 🟢 Complete ~92% Metadata, manifest, spine, collections, Schematron-equivalent checks
    Content Documents 🟢 Complete ~93% XHTML structure, CSS url(), @import, SVG, entities, title, SSML, XML version
    Navigation Document 🟢 Complete ~95% Nav content model, landmarks, labels, reading order, hidden, nested-ol
    Schema Validation 🟡 Partial ~55% RelaxNG for OPF/container; XHTML/SVG disabled (libxml2 limitation)
    CSS 🟡 Partial ~85% @font-face, @import, url() extraction, position, forbidden properties, alt style tags
    Cross-reference Validation 🟢 Complete ~92% Reference tracking, fragments, fallbacks, remote resources, cross-document features
    Accessibility Checks 🟢 Complete ~71% 12/17 ACC checks: table, image alt, hyperlink, MathML, SVG, epub:type, OPF metadata
    Media Overlays 🟡 Partial ~70% SMIL structure, timing, audio, OPF metadata, duration validation
    Media Validation ❌ Not Started 0% Planned

    Legend: 🟢 Complete | 🟡 Partial | 🔴 Basic | ❌ Not Started

    Overall Progress: ~93% of Java EPUBCheck features

    See PROJECT_STATUS.md for detailed comparison.

    • Node.js 18+
    • npm 9+
    # Clone the repository
    git clone https://github.com/likecoin/epubcheck-ts.git
    cd epubcheck-ts

    # Install dependencies
    npm install

    # Run tests
    npm test

    # Build
    npm run build
    Script Description
    npm run build Build the library (ESM + CJS)
    npm run dev Build in watch mode
    npm test Run tests in watch mode
    npm run test:run Run tests once
    npm run test:coverage Run tests with coverage
    npm run lint Lint with ESLint
    npm run lint:fix Lint and auto-fix
    npm run format Format with Biome
    npm run typecheck TypeScript type checking
    npm run check Run all checks (format + typecheck)
    npm run docs Generate API docs (HTML + Markdown)
    npm run docs:html Generate HTML API docs to docs/html/
    npm run docs:md Generate Markdown API docs to docs/md/ 
    epubcheck-ts/
    ├── src/
    │   ├── index.ts           # Public API exports
    │   ├── checker.ts         # Main EpubCheck class
    │   ├── types.ts           # TypeScript type definitions
    │   ├── core/              # Core validation logic
    │   ├── ocf/               # OCF container validation ✅
    │   ├── opf/               # Package document validation ✅
    │   ├── content/           # Content document validation ✅
    │   ├── nav/               # Navigation validation ✅
    │   ├── ncx/               # NCX validation (EPUB 2) ✅
    │   ├── references/        # Cross-reference validation ✅
    │   ├── schema/            # Schema validation ✅
    │   │   ├── relaxng.ts     # RelaxNG validation
    │   │   ├── xsd.ts         # XSD validation
    │   │   ├── schematron.ts  # Schematron validation
    │   │   └── orchestrator.ts # Schema orchestration
    │   └── messages/          # Error messages
    ├── schemas/               # Schema files (RNG, RNC, SCH)
    ├── test/
    │   ├── fixtures/          # Test EPUB files
    │   └── integration/       # Integration tests
    ├── docs/
    │   └── md/                # Generated API docs (Markdown, checked in)
    ├── examples/
    │   └── web/               # Web demo ✅
    └── dist/                  # Build output

    Legend: ✅ Implemented

    Aspect epubcheck-ts EPUBCheck (Java)
    Runtime Node.js / Browser JVM
    Feature Parity ~93% 100%
    Bundle Size ~450KB JS + ~1.6MB WASM ~15MB
    Installation npm install Download JAR
    Integration Native JS/TS CLI or Java API
    Performance Comparable Baseline

    See PROJECT_STATUS.md for detailed feature comparison.

    Contributions are welcome! Please read CONTRIBUTING.md for guidelines.

    For AI agents contributing to this project, see AGENTS.md.

    GPL-3.0

    This is an independent TypeScript implementation inspired by the Java-based EPUBCheck (BSD-3-Clause). No code was directly copied from the original project.

    This project is built and maintained by the 3ook.com team. 3ook is a Web3 eBook platform where authors can publish EPUB ebooks and readers can collect them as digital assets. If you're an author looking to publish your ebook, check out 3ook.com.

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