alextanhongpin / compress.js

A simple JavaScript based client-side image compression algorithm

compress.js

A JavaScript client side image compression. This library uses the Canvas API to compress the image, and thus will not work on the node.js server-side.

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Advantage:

• quick compression on the client-side
• save data by compressing it on the client-side before sending to the server
• mantains the aspect ratio of the images when resizing
• fix image rotation issue when uploading images from Android an iOS
• supports cropping the image
• New: supports cropping to desired aspect ratio, e.g. 1:1, 4:3 etc

NOTE:

There are several limitations for this library:

• When working with image/gif, the compressed image will no longer animate.
• When working with image/png with transparent background, the compressed image will lose transparency and result in black background.

Installation

NPM Package here.

npm install compress.js --save

CDN

Using jsDelivr CDN:

Important

The script tag must include type="module" to work.

<!-- index.js is your file that needs to execute compress.js-->
<script src="./index.js" type="module"></script>

And in your index.js, you can import the desired version:

// index.js
"use strict";

import Compress from "https://cdn.jsdelivr.net/npm/[email protected]/build/compress.min.js";

const compressor = new Compress();

Import

const Compress = require('compress.js')

You can also include the build/compress.min.js in your project directory, and then importing it using type module in the script tag.

<!-- index.html -->
<script type="module" src="index.js"></script>

// index.js
import Compress from "./compress.min.js";

// ...

Demo

Try out our demo here.

Usage

import Compress from "./compress.min.js";

const compressor = new Compress();

// Listen to file upload events.
upload.addEventListener(
  "change",
  async function (evt) {
	const file = evt.target.files[0];
    const newFile = await compressor.compress(file, {
      quality: 0.95,
      crop: true, // If true, will crop a square image from the center.
      maxWidth: 320, // Image width will not exceed 320px.
      maxHeight: 320, // Image height will not exceed 320px.
    });

    // Display the image on the img element.
    img.src = URL.createObjectURL(newFile);
  },