heic-convert

Convert HEIC/HEIF images to JPEG and PNG

Install

npm install heic-convert

Usage in NodeJS

Convert the main image in a HEIC to JPEG

const { promisify } = require('util');
const fs = require('fs');
const convert = require('heic-convert');

(async () => {
  const inputBuffer = await promisify(fs.readFile)('/path/to/my/image.heic');
  const outputBuffer = await convert({
    buffer: inputBuffer, // the HEIC file buffer
    format: 'JPEG',      // output format
    quality: 1           // the jpeg compression quality, between 0 and 1
  });

  await promisify(fs.writeFile)('./result.jpg', outputBuffer);
})();

Convert the main image in a HEIC to PNG

const { promisify } = require('util');
const fs = require('fs');
const convert = require('heic-convert');

(async () => {
  const inputBuffer = await promisify(fs.readFile)('/path/to/my/image.heic');
  const outputBuffer = await convert({
    buffer: inputBuffer, // the HEIC file buffer
    format: 'PNG'        // output format
  });

  await promisify(fs.writeFile)('./result.png', outputBuffer);
})();

Convert all images in a HEIC

const { promisify } = require('util');
const fs = require('fs');
const convert = require('heic-convert');

(async () => {
  const inputBuffer = await promisify(fs.readFile)('/path/to/my/image.heic');
  const images = await convert.all({
    buffer: inputBuffer, // the HEIC file buffer
    format: 'JPEG'       // output format
  });

  for (let idx in images) {
    const image = images[idx];
    const outputBuffer = await image.convert();
    await promisify(fs.writeFile)(`./result-${idx}.jpg`, outputBuffer);
  }
})();

The work to convert an image is done when calling image.convert(), so if you only need one of the images in a multi-image file, you can convert just that one from the images array and skip doing any work for the remaining images.

Note that while the converter returns a Promise and is overall asynchronous, a lot of work is still done synchronously, so you should consider using a worker thread in order to not block the main thread in highly concurrent production environments.

Usage in the browser

While the NodeJS version of heic-convert may be compiled for use in the browser with something like webpack, not all build tools necessarily like to compile all modules well. However, what further complicates things is that this module uses pure-javascript implementations of a jpeg and png encoder. But the browser has its own native encoders! Let's just use those instead of including a ton of extra code in your bundle.

When compiling a client-side project, use:

const convert = require('heic-convert/browser');

This is currently only supported in the main thread. Support for workers may be added in the future, but if you need it sooner, please create an issue or even a PR!

Related

• heic-cli - convert heic/heif images to jpeg or png from the command line
• heic-decode - decode heic images to raw image data
• libheif-js - libheif as a pure-javascript npm module