heic-converter

Convert HEIC images to PNG/JPEG entirely in the browser using libheif-js.

Try the Live Demo

Features

• Zero backend dependencies - Runs entirely in the browser using WebAssembly
• Simple API - Clear function names and straightforward usage
• TypeScript support - Full type definitions included
• Multi-image support - Handle HEIC files with multiple images (bursts)
• Privacy-focused - All processing happens client-side

Installation

npm install heic-converter

Quick Start

import { heicToPng, heicToJpeg } from 'heic-converter';

// Convert HEIC to PNG
const pngBlob = await heicToPng(heicFile);

// Convert HEIC to JPEG with quality setting
const jpegBlob = await heicToJpeg(heicFile, { quality: 0.8 });

Usage

Convert to PNG

import { heicToPng } from 'heic-converter';

const pngBlob = await heicToPng(heicFile);
const url = URL.createObjectURL(pngBlob);

Convert to JPEG

import { heicToJpeg } from 'heic-converter';

const jpegBlob = await heicToJpeg(heicFile, { quality: 0.92 });

Handle Multi-Image HEIC Files

HEIC files can contain multiple images (e.g., burst photos):

import { heicToPng } from 'heic-converter';

const pngBlobs = await heicToPng(heicFile, { multiple: true });
pngBlobs.forEach((blob, index) => {
  console.log(`Image ${index + 1}:`, blob);
});

Check if File is HEIC

import { isHeic } from 'heic-converter';

if (await isHeic(file)) {
  const pngBlob = await heicToPng(file);
}

Advanced Usage

import { convert } from 'heic-converter';

const blob = await convert(heicFile, {
  format: 'jpeg',
  quality: 0.95,
  multiple: false
});

API Reference

heicToPng(blob, options?)

Converts a HEIC image to PNG format.

| Parameter | Type | Description | |-----------|------|-------------| | blob | Blob | The HEIC image to convert | | options.multiple | boolean | Extract all images from multi-image HEIC files (default: false) |

Returns: Promise<Blob> or Promise<Blob[]> if multiple is true

heicToJpeg(blob, options?)

Converts a HEIC image to JPEG format.

| Parameter | Type | Description | |-----------|------|-------------| | blob | Blob | The HEIC image to convert | | options.quality | number | JPEG quality between 0 and 1 (default: 0.92) | | options.multiple | boolean | Extract all images from multi-image HEIC files (default: false) |

Returns: Promise<Blob> or Promise<Blob[]> if multiple is true

convert(blob, options)

Generic conversion function for advanced use cases.

| Parameter | Type | Description | |-----------|------|-------------| | blob | Blob | The HEIC image to convert | | options.format | 'png' \| 'jpeg' | Output format (required) | | options.quality | number | JPEG quality between 0 and 1 (default: 0.92, ignored for PNG) | | options.multiple | boolean | Extract all images from multi-image HEIC files (default: false) |

Returns: Promise<Blob> or Promise<Blob[]> if multiple is true

isHeic(blob)

Checks if a file is a HEIC/HEIF image by examining its file signature.

| Parameter | Type | Description | |-----------|------|-------------| | blob | Blob | The file to check |

Returns: Promise<boolean> - true if the file is HEIC/HEIF

TypeScript

Full TypeScript support with included type definitions:

import type { ConvertOptions, ConvertOptionsWithFormat } from 'heic-converter';

interface ConvertOptions {
  quality?: number;      // 0-1 for JPEG (default: 0.92)
  multiple?: boolean;    // Handle multi-image HEIC files (default: false)
}

interface ConvertOptionsWithFormat extends ConvertOptions {
  format: 'png' | 'jpeg';
}

Browser Support

Requires a modern browser with:

• WebAssembly support
• Canvas API
• ES2020+ features

Supported browsers:

• Chrome/Edge 87+
• Firefox 89+
• Safari 15+

How It Works

1. Uses libheif-js (WebAssembly) to decode HEIC to raw image data
2. Renders the decoded data to an HTML Canvas
3. Exports the canvas as PNG or JPEG Blob
4. All processing happens entirely in the browser - no server uploads

License

MIT

Contributing

Contributions are welcome! Please open an issue or pull request on GitHub.

Credits

Built with libheif-js, the WebAssembly build of libheif.