# Browser Image Compression #
[![npm](https://img.shields.io/npm/v/browser-image-compression.svg)](https://www.npmjs.com/package/browser-image-compression)
[![npm](./coverage/badge.svg)](https://github.com/Donaldcwl/browser-image-compression)
[![npm](https://img.shields.io/npm/l/browser-image-compression.svg)](https://github.com/Donaldcwl/browser-image-compression)

Javascript module to be run in the web browser for image compression.

## Features ##
- You can use this module to compress jpeg and png image by reducing **resolution** or **storage size** before uploading to application server to save bandwidth.
- **Multi-thread** (web worker) non-blocking compression are supported through options.

## Install ##
You can download imageCompression from the [dist folder][dist]. Alternatively, you can install it via yarn or npm
```
npm install browser-image-compression --save
or
yarn add browser-image-compression
```
or use a CDN like [delivrjs]:
```
https://cdn.jsdelivr.net/npm/browser-image-compression@1.0.13/dist/browser-image-compression.js
or
https://cdn.jsdelivr.net/npm/browser-image-compression@latest/dist/browser-image-compression.js
```

## How to use this module in your project? ##
#### Use as ES module ####

(can be used in framework like React, Angular, Vue etc)

(work with bundler like webpack and rollup)
```javascript
import imageCompression from 'browser-image-compression';
```

or

#### In html file ####
```html
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/browser-image-compression@1.0.13/dist/browser-image-compression.js"></script>
```

## API ##
### Main function ###
```javascript
// you should provide one of maxSizeMB, maxWidthOrHeight in the options
const options = { 
  maxSizeMB: number,          // (default: Number.POSITIVE_INFINITY)
  maxWidthOrHeight: number,   // compressedFile will scale down by ratio to a point that width or height is smaller than maxWidthOrHeight (default: undefined)
  onProgress: Function,       // optional, a function takes one progress argument (percentage from 0 to 100) 
  useWebWorker: boolean,      // optional, use multi-thread web worker, fallback to run in main-thread (default: true)

  // following options are for advanced users
  maxIteration: number,       // optional, max number of iteration to compress the image (default: 10)
  exifOrientation: number,    // optional, see https://stackoverflow.com/a/32490603/10395024
  fileType: string,           // optional, fileType override
  initialQuality: number      // optional, initial quality value between 0 and 1 (default: 1)
}

imageCompression(file: File, options): Promise<File>
```
### Helper function ###
- for advanced users only, most users won't need to use the helper functions
```javascript
imageCompression.getDataUrlFromFile(file: File): Promise<base64 encoded string>
imageCompression.getFilefromDataUrl(dataUrl: string, filename: string, lastModified?: number): Promise<File>
imageCompression.loadImage(url: string): Promise<HTMLImageElement>
imageCompression.drawImageInCanvas(img: HTMLImageElement): HTMLCanvasElement | OffscreenCanvas
imageCompression.drawFileInCanvas(file: File): Promise<[ImageBitmap | HTMLImageElement, HTMLCanvasElement | OffscreenCanvas]>
imageCompression.canvasToFile(canvas: HTMLCanvasElement | OffscreenCanvas, fileType: string, fileName: string, fileLastModified: number, quality?: number): Promise<File>
imageCompression.getExifOrientation(file: File): Promise<number> // based on https://stackoverflow.com/a/32490603/10395024
```

## Usage ##
```html
<input type="file" accept="image/*" onchange="handleImageUpload(event);">
```
async await syntax:
```javascript
async function handleImageUpload(event) {

  const imageFile = event.target.files[0];
  console.log('originalFile instanceof Blob', imageFile instanceof Blob); // true
  console.log(`originalFile size ${imageFile.size / 1024 / 1024} MB`);

  const options = {
    maxSizeMB: 1,
    maxWidthOrHeight: 1920,
    useWebWorker: true
  }
  try {
    const compressedFile = await imageCompression(imageFile, options);
    console.log('compressedFile instanceof Blob', compressedFile instanceof Blob); // true
    console.log(`compressedFile size ${compressedFile.size / 1024 / 1024} MB`); // smaller than maxSizeMB

    await uploadToServer(compressedFile); // write your own logic
  } catch (error) {
    console.log(error);
  }

}
```
Promise.then().catch() syntax:
```javascript
function handleImageUpload(event) {

  var imageFile = event.target.files[0];
  console.log('originalFile instanceof Blob', imageFile instanceof Blob); // true
  console.log(`originalFile size ${imageFile.size / 1024 / 1024} MB`);

  var options = {
    maxSizeMB: 1,
    maxWidthOrHeight: 1920,
    useWebWorker: true
  }
  imageCompression(imageFile, options)
    .then(function (compressedFile) {
      console.log('compressedFile instanceof Blob', compressedFile instanceof Blob); // true
      console.log(`compressedFile size ${compressedFile.size / 1024 / 1024} MB`); // smaller than maxSizeMB

      return uploadToServer(compressedFile); // write your own logic
    })
    .catch(function (error) {
      console.log(error.message);
    });
}
```

## Demo / Example ##
open https://donaldcwl.github.io/browser-image-compression/example/basic.html

or check the "[example]" folder in this repo

## Browsers support ##

| [<img src="https://raw.githubusercontent.com/godban/browsers-support-badges/master/src/images/edge.png" alt="IE / Edge" width="16px" height="16px" />](http://godban.github.io/browsers-support-badges/)</br>IE / Edge | [<img src="https://raw.githubusercontent.com/godban/browsers-support-badges/master/src/images/firefox.png" alt="Firefox" width="16px" height="16px" />](http://godban.github.io/browsers-support-badges/)</br>Firefox | [<img src="https://raw.githubusercontent.com/godban/browsers-support-badges/master/src/images/chrome.png" alt="Chrome" width="16px" height="16px" />](http://godban.github.io/browsers-support-badges/)</br>Chrome | [<img src="https://raw.githubusercontent.com/godban/browsers-support-badges/master/src/images/safari.png" alt="Safari" width="16px" height="16px" />](http://godban.github.io/browsers-support-badges/)</br>Safari | [<img src="https://raw.githubusercontent.com/godban/browsers-support-badges/master/src/images/opera.png" alt="Opera" width="16px" height="16px" />](http://godban.github.io/browsers-support-badges/)</br>Opera | [<img src="https://raw.githubusercontent.com/godban/browsers-support-badges/master/src/images/chrome-android.png" alt="Chrome for Android" width="16px" height="16px" />](http://godban.github.io/browsers-support-badges/)</br>Chrome for Android |
| --------- | --------- | --------- | --------- | --------- | --------- |
| IE10, IE11, Edge| last 2 versions| last 2 versions| last 2 versions| last 2 versions| last 2 versions

## IE support ##
Promise API is being used in this library. If you need to support browser that do not support Promise like IE. You can include the Promise polyfill in your project.

See: https://github.com/taylorhakes/promise-polyfill

You can include the following script to load the Promise polyfill:
```html
<script src="https://cdn.jsdelivr.net/npm/promise-polyfill@8/dist/polyfill.min.js"></script>
```

## Typescript type definitions ##
Typescript definitions are included in the package & referenced in the `types` section of the `package.json`

## Contribution ##
1. fork the repo and git clone it
2. run `npm run watch` # it will watch code change in lib/ folder and generate js in dist/ folder
3. add/update code in lib/ folder
4. try the code by opening example/development.html which will load the js in dist/ folder
5. add/update test in test/ folder
6. `npm run test`
7. push to your forked repo on github
8. make a pull request to this repo

[dist]: https://github.com/Donaldcwl/browser-image-compression/tree/master/dist
[example]: https://github.com/Donaldcwl/browser-image-compression/tree/master/example
[delivrjs]: https://cdn.jsdelivr.net/