@molecule/api-pdf-pdfkit

Auto-generated, AI-first package reference for the molecule.dev ecosystem. It is written to be read by coding agents as much as by people, and is generated from this package's source — edit src/index.ts JSDoc, not this file.

PDFKit programmatic PDF generation provider for molecule.dev.

Uses PDFKit for creating PDFs from HTML or templates, and pdf-lib for manipulating existing PDFs (merge, watermark, page count, metadata). Best suited for programmatic PDF generation. For high-fidelity HTML-to-PDF rendering, use @molecule/api-pdf-puppeteer instead.

Quick Start

import { setProvider } from '@molecule/api-pdf'
import { provider } from '@molecule/api-pdf-pdfkit'

setProvider(provider)

// Or create with custom config:
import { createProvider } from '@molecule/api-pdf-pdfkit'
const customProvider = createProvider({ defaultFont: 'Helvetica', defaultFontSize: 14 })
setProvider(customProvider)

Type

provider

Installation

npm install @molecule/api-pdf-pdfkit @molecule/api-pdf pdf-lib pdfkit
npm install -D @types/pdfkit

API

Interfaces

PDFKitConfig

Configuration options for the PDFKit PDF provider.

interface PDFKitConfig {
  /**
   * Default font to use for text rendering.
   * Must be a standard PDF font or a path to a font file.
   * Defaults to `'Helvetica'`.
   */
  defaultFont?: string

  /**
   * Default font size in points.
   * Defaults to `12`.
   */
  defaultFontSize?: number

  /**
   * Default line height multiplier.
   * Defaults to `1.2`.
   */
  lineHeight?: number

  /**
   * Opening delimiter for simple template interpolation in `fromTemplate`.
   * Defaults to `'{{'`.
   */
  templateOpenDelimiter?: string

  /**
   * Closing delimiter for simple template interpolation in `fromTemplate`.
   * Defaults to `'}}'`.
   */
  templateCloseDelimiter?: string
}

Functions

createProvider(config)

Creates a PDFKit-backed PDF provider.

function createProvider(config?: PDFKitConfig): PDFProvider

• config — Optional provider configuration.

Returns: A PDFProvider backed by PDFKit and pdf-lib.

Constants

provider

The provider implementation, lazily initialized with default config.

const provider: PDFProvider

Core Interface

Implements @molecule/api-pdf interface.

Bond Wiring

Setup function to register this provider with the core interface:

import { setProvider } from '@molecule/api-pdf'
import { provider } from '@molecule/api-pdf-pdfkit'

export function setupPdfPdfkit(): void {
  setProvider(provider)
}

Injection Notes

Requirements

Peer dependencies:

• @molecule/api-pdf ^1.0.1

Runtime Dependencies

• @molecule/api-pdf
• pdf-lib
• pdfkit

fromHTML is a rudimentary HTML renderer, not a browser. It understands ONLY h1–h6, p, br, hr, b/strong, i/em, and ul/ol/li; any other tag renders as its plain text content, and CSS, tables, images, links, and attributes are ignored entirely. Feed it simple semantic markup (or use fromTemplate with {{key}} interpolation); switch to @molecule/api-pdf-puppeteer when the PDF must look like the HTML.

This bond does NOT implement the core contract's optional toImages() — calling it is a runtime "not a function" error. The puppeteer bond implements it; swap bonds if you need page-to-image rendering.

E2E Tests

Integration checklist — drive the real UI (live preview, no mocks), adapt each item to this app's actual documents (invoice, report, receipt, contract) and check every box off one by one. A box you can't check is an integration bug to fix — not a skip:

• [ ] Every document the app generates has a working Download/Export control that returns a REAL PDF — not an HTML error page or a JSON-stringified Buffer. Inspect the actual response: Content-Type is application/pdf and the body's first bytes are the %PDF magic (hex 25 50 44 46). Fetch the endpoint and check both — a body that starts with < or { is a failure dressed up as a download.
• [ ] Opening the downloaded PDF shows the record's real values (names, line items, dates, totals) — not placeholder/template text or a blank page.
• [ ] Edit a record and re-export: the new PDF reflects the changed values, and two different records produce two visibly different PDFs (not the same cached bytes for every id).
• [ ] If the app shows page previews or reads document info, it feature-detects (getProvider().toImages / .getMetadata) or bonds a provider that supports them — both are OPTIONAL and THROW on bonds that lack them (e.g. PDFKit), so a preview built on an unsupporting bond errors at runtime, not compile time.
• [ ] Styled output (CSS layout, backgrounds, web fonts) actually renders — which requires a browser-engine bond (Puppeteer). On PDFKit the same HTML collapses to a plain-text approximation; if the design matters, that's the wrong bond.
• [ ] Export is authorized: a signed-in user cannot fetch another user's document by guessing or incrementing an id — the endpoint scopes every PDF to its owner (a guessed id returns 403/404, never someone else's invoice).