icojs

A JavaScript library to use ICO. Works on both Node.js and the browser.

Install

npm install icojs

Node.js:

import { isICO, parseICO } from 'icojs';

Browser:

import { isICO, parseICO } from 'icojs/browser';

or

<script type="text/javascript" src="node_modules/icojs/dist/ico.js"></script>

To fully use this library, browsers must support JavaScript typed arrays, Canvas API and Promise. Chrome, Edge 12, Firefox and Safari 9 support these functions.

Example

Node.js:

import { readFile, writeFile } from 'node:fs/promises';
import { parseICO } from 'icojs';

const buffer = await readFile('favicon.ico');
const images = await parseICO(buffer, 'image/png');
// save as png files
images.forEach(image => {
  const file = `${image.width}x${image.height}-${image.bpp}bit.png`;
  const data = Buffer.from(image.buffer);
  writeFile(file, data);
});

Browser:

<input type="file" id="input-file" />
<script>
  document.getElementById('input-file').addEventListener('change', evt => {
    // use FileReader for converting File object to ArrayBuffer object
    var reader = new FileReader();
    reader.onload = async e => {
      const images = await ICO.parseICO(e.target.result);
      // logs images
      console.dir(images);
    };
    reader.readAsArrayBuffer(evt.target.files[0]);
  }, false);
</script>

Demo

https://egy186.github.io/icojs/#demo

API

ICO

• ICO
  • isICO(source) ⇒ boolean ⏏
  • parseICO(buffer, [mime]) ⇒ Promise.<Array.<ParsedImage>> ⏏

isICO(source) ⇒ boolean ⏏

Check the ArrayBuffer is valid ICO.

Kind: global method of ICO
Returns: boolean - True if arg is ICO.

Param	Type	Description
source	ArrayBuffer | Buffer	ICO file data.

parseICO(buffer, [mime]) ⇒ Promise.<Array.<ParsedImage>> ⏏

Parse ICO and return some images.

Kind: global method of ICO
Returns: Promise.<Array.<ParsedImage>> - Resolves to an array of ParsedImage.

Param	Type	Default	Description
buffer	ArrayBuffer | Buffer		ICO file data.
[mime]	string	"image/png"	MIME type for output.

Typedefs

ParsedImage : object

Kind: global typedef
Properties

Name	Type	Description
width	number	Image width.
height	number	Image height.
bpp	number	Image color depth as bits per pixel.
buffer	ArrayBuffer	Image buffer.

License

MIT license