noicejs

extremely thin async dependency injection

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Project maintained by ssube Hosted on GitHub Pages — Theme by mattgraham

noicejs

Extremely thin, async dependency injection, now with a getting started guide.

Inspired by Google’s Guice library and written in Typescript.

Features

• async dependency resolution
• constructor and property injection
• modular containers with inheritance
• named dependencies using strings or unique symbols
• typed errors
• typescript typedefs
• zero runtime dependencies, bundled or otherwise
• extensive test coverage

Contents

• noicejs
  • Features
  • Contents
  • Status
  • Releases
  • Usage
  • Build
  • License

Status

Releases

Usage

Consider a Server class that needs to fetch data from the Cache and Filesystem, but doesn’t know (or need to know) how those are implemented.

import { Cache, Filesystem } from './interfaces';
import { LocalModule } from './local';
import { NetworkModule } from './network';

@Inject(Cache, Filesystem)
class Server {
  protected readonly cache: Cache;
  protected readonly filesystem: Filesystem;
  protected readonly ttl: number;

  constructor(options) {
    this.cache = options.cache;
    this.filesystem = options.filesystem;
    this.ttl = defaultTo(options.ttl, 0);
  }

  get(path: string) {
    return options.cache.get(path, this.ttl, () => options.filesystem.get(path));
  }
}

function module() {
  if (process.env['DEBUG'] === 'TRUE') {
    return new LocalModule();
  } else {
    return new NetworkModule();
  }
}

async function main() {
  const container = Container.from(module());
  await container.configure();

  const foo = await container.create(Server, {
    /* cache and filesystem are found and injected by container */
    ttl: 60,
  });
}

noicejs will collect dependencies from the decorated constructor and any superclasses, find a provider for each injected dependency, and asynchronously resolve them before calling the constructor. Any extra parameters are passed on to the original constructor, along with the container and resolved dependencies.

Build

To build a bundle and run tests:

> make

yarn
yarn install v1.17.3
[1/4] Resolving packages...
success Already up-to-date.
Done in 0.20s.
/home/ssube/code/ssube/noicejs//node_modules/.bin/rollup --config /home/ssube/code/ssube/noicejs//config/rollup.js

src/index.ts, test/harness.ts, test/**/Test*.ts → out/...
...
created out/ in 3.3s
/home/ssube/code/ssube/noicejs//node_modules/.bin/api-extractor run --config /home/ssube/code/ssube/noicejs//config/api-extractor.json --local -v

api-extractor 7.3.8  - https://api-extractor.com/
...

API Extractor completed successfully
Success!

License