try-di

Try DI is a simple, typesafe and lightweight dependency injection container for TypeScript. Designed with the idea to avoid having runtime errors due to missing, incorrect or outdated mapping configuration.

• Safe. It type-checks every mapping. Allows to verify all the mappings in auto-tests (= on CI).
• Fast. TODO: need to measure a sample
• Simple. It supports the minimum required and sufficient functionality for most apps.
• Small. 1.22 kilobytes (minified and gzipped). No dependencies. Size Limit controls the size.

import { createContainer } from 'try-di';

const { setValue, setFactory, setClass, resolve } = createContainer();

setValue({ for: Water, use: new Water() });
setFactory({ for: Fish, use: () => new Fish(resolve(Water)) });
setClass({ for: Animal, use: Cat, inject: [Fish, Water] });

assert.ok(resolve(Animal), "Cat wasn't resolved");

Supports modern browsers, IE and Node.js. Provides modern ES2019 and CommonJS bundles, as well as legacy ones (ES5).

Verify all the dependency mappings in auto-tests

Medium to large projects can have quite a few dependency mappings and sometimes it's easy to just forget to map/register some of the required dependencies and end up with a runtime error. This container allows you to be sure that all the dependencies can be resolved by using container.verifyAll() in your automated-tests (usually they are run on CI)

import { createContainer } from 'try-di';
import { buildYourContainer } from '../app-di';

it('all production container dependencies can be resolved', () => {
  const container = buildYourContainer();
  container.verifyAll(); // fails the test as `Water` mapping is missing
});

// app-di.js
export function buildYourContainer() {
  const container = createContainer();
  const { setValue, setFactory, resolve } = container;

  // setValue({ for: Water, use: new Water() });
  setFactory({ for: Fish, use: () => new Fish(resolve(Water)) });

  return container;
}

TODO: more samples with type-checks and all possible ways to register deps