@printedjs/polyfill

Compatibility polyfills for older browsers running Printedjs.

@printedjs/polyfill provides standard DOM, observer, and modern JavaScript feature shims required by older browsers (such as older Safari, older Chrome < 86, and legacy Android WebViews) to run Printedjs smoothly.

Features

• DOM Slicing & Manipulation Shims — Polyfills replaceChildren, replaceWith, remove, append, and prepend on Element, DocumentFragment, and CharacterData.
• Layout Observers — Provides fallback implementations for ResizeObserver and IntersectionObserver when missing in legacy browser runtimes.
• Asynchronous Execution Helpers — Shims requestIdleCallback, cancelIdleCallback, and queueMicrotask.
• Modern JavaScript Standards — Implements Object.hasOwn, Array.prototype.at, String.prototype.replaceAll, Promise.allSettled, structuredClone, and CSS.supports.
• Zero Engine Overhead — Contains no layout engine or parser code; pure runtime shims only.

Installation

pnpm add @printedjs/polyfill

Or load directly via script tag:

<script src="node_modules/@printedjs/polyfill/dist/index.min.global.js"></script>

Usage

1. Browser Script Tag (Legacy Browser Support)

Load the polyfill script before loading @printedjs/minimal or @printedjs/browser:

<!DOCTYPE html>
<html>
	<head>
		<!-- Polyfills for older browsers -->
		<script src="/path/to/index.min.global.js"></script>

		<!-- Printedjs Minimal Engine -->
		<script src="/path/to/index.min.global.js"></script>

		<style>
			@page {
				size: A4;
				margin: 20mm;
			}
		</style>
	</head>
	<body>
		<h1>Document Title</h1>
		<p>Rendered cleanly on modern and legacy browsers alike.</p>
	</body>
</html>

2. Programmatic Import

import { installPolyfills } from "@printedjs/polyfill";

// Ensure all polyfills are installed in the global environment
installPolyfills();

When Do You Need This?

• Modern Browsers (Evergreen Chrome, Edge, Safari, Firefox): You do not need this package. Simply use @printedjs/minimal or @printedjs/browser.
• Legacy Browsers & WebViews: Use this package if targeting:
  • Safari < 14
  • Chrome < 86
  • Older Android WebViews
  • Embedded browser environments lacking ES2022 / modern DOM APIs

License

MIT