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What this is

ngx-media-optimizer is a TypeScript library that converts and compresses images entirely on the client side, using the browser's native OffscreenCanvas and createImageBitmap APIs. No server round-trips, no C++ WASM blobs, no third-party image libraries.

Formats supported: WebP · AVIF · JPEG · PNG

Works with Angular, React, Vue, and plain JavaScript. Zero runtime dependencies.

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Install

npm install ngx-media-optimizer

For the full API reference and framework-specific quick starts see the package README.

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Highlights

• Zero extra dependencies — native OffscreenCanvas replaces browser-image-compression
• Parallel batch processing — auto-detected concurrency, configurable via concurrency option
• Binary-search quality — finds the highest quality that fits a maxSizeMB budget (5 iterations, ±2%)
• Stepwise halving resize — avoids quality loss from a single large downscale
• Discriminated union state — compressedUrl / compressedSize only accessible after status === 'completed'
• Reactive callbacks — framework-agnostic onImagesChange / onUploadingChange pattern
• ImageUtilsService — standalone utility for validation, analysis, thumbnails, and format probing
• 228 tests

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Quick example

import { ImageConverterService } from 'ngx-media-optimizer';

const svc = new ImageConverterService();

svc.onImagesChange(images => console.log(images));

await svc.convertFormat(fileList, {
  outputFormat: 'webp',
  quality: 80,
  maxSizeMB: 1,
});

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What''s new in v2

	v1	v2
Encoding engine	browser-image-compression (libvips)	Native OffscreenCanvas
Dependencies	1	0
getSupportedFormats()	—	Probes actual browser codec support
estimateCompressedSize()	—	Fast synchronous heuristic
getBestQuality()	—	Binary-search quality for a target size
hasTransparency()	—	Useful before converting PNG → JPEG
isAnimated()	—	Detects animated GIF / WebP
sortOrder option	—	Sort batch by file size before processing
useWebWorker	Feature	Removed in v2.0.1

Breaking change: Encoding results will differ slightly from v1 because native codec quality curves differ from libvips. The API is otherwise unchanged, apart from method renames:

v1	v2
validateImage(file)	isValidImage(file)
shouldCompress(file, n)	needsCompression(file, n)

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Repository structure

media-optimizer-workspace/
├── projects/
│   └── media-optimizer/        # The npm library
│       ├── src/lib/
│       │   ├── media-optimizer.service.ts   # ImageConverterService
│       │   ├── image-utils.service.ts       # ImageUtilsService
│       │   └── shared/
│       │       ├── image-codec.ts           # NativeImageCodec (OffscreenCanvas pipeline)
│       │       ├── image-helpers.ts
│       │       ├── lru-cache.ts
│       │       ├── subject.ts               # Zero-dep reactive primitive
│       │       └── types.ts
│       └── README.md                        # API docs published to npm
├── angular.json
├── rollup.config.mjs
└── CHANGELOG.md

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Development

Setup

git clone https://github.com/barbozaa/media-optimizer-workspace.git
cd media-optimizer-workspace
npm install

Commands

Command	What it does
npm run build:lib	Build + rollup the library into dist/media-optimizer/
npm run pack:lib	Build + pack a local .tgz for testing
npx vitest run	Run the 228 tests
npx vitest --watch	Run tests in watch mode

Testing

npx vitest run

228 tests across image-utils.service.spec.ts and media-optimizer.service.spec.ts.

Publishing

npm run build:lib
cd dist/media-optimizer
npm publish

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Contributing

Issues and pull requests are welcome. Please open an issue first if you are planning a large change.

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Changelog

See CHANGELOG.md.

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License

MIT © Barboza