@travisk/tiny-ioc v0.0.2

IoC / DI Container

This is a minimal IoC / DI Container that supports injection of dependencies for TypeScript.

Feature Set:

• Object injection
• constructor injection
• Singleton / Transient services for class instantiation
• Can support multiple containers but initial @Service are registered on each container created

Installation

Install the package via npm

npm install @travisk/tiny-ioc

Ensure you install reflect-metadata as this library requires it

npm install reflect-metadata

Import reflect-metadata when using the decorators such as @Service

import 'reflect-metadata';

Enable decorators and metadata within your tsconfig.json

"emitDecoratorMetadata": true,
"experimentalDecorators": true,

Usage

Injecting constructor dependencies (Transient by default)

• Use @Service above the class declaration to allow constructor injection

import 'reflect-metadata';
import { Container, Service } from '@travisk/tiny-ioc';

class UserRepository {

    getAllUserIds(): number[] {
        return [1, 2];
    }

}


@Service()
class UserService {

    constructor(private userRepo: UserRepository) {}

    getUserData = (): number[] => {
        return this.userRepo.getAllUserIds();
    }
}

const container = new Container();
const userService = container.get(UserService);

const userIds = userService.getUserData(); // returns [1, 2]

Injecting Singleton dependencies

import 'reflect-metadata';
import { Container, Service } from '@travisk/practice-lib';

class UuidGenerator {
    private uuid;
    constructor(){
        this.uuid = new randomUuid(); // generate uuid
    }
    getUuid(): string {
        return this.uuid;
    }

}


@Service('Singleton')
class TestClass {

    constructor(private uuidGen: UuidGenerator) {}

    getUserId = (): string => {
        return this.uuidGen.getUuid();
    }
}

const container = new Container();
const service1 = container.get(TestClass);
const service2 = container.get(TestClass);

service1.getUserId() === service2.getUserId(); // returns true

Injecting Objects

import 'reflect-metadata';
import { Container } from '@travisk/tiny-ioc';


const container = new Container();
container.register('token', {hello: 'world'});
const obj = container.get('token'); // returns { hello: 'world' }

Roadmap / Missing features

• Include injection of functions, constants etc
• Allow for Scoped lifecycle dependencies
• Allow injected dependencies to be swapped with 'Fake' dependencies for testing

For Maintainors / Contributors

• make sure to run lint via npm run lint
• This library is published via changesets
  • You can run npx changeset to initialise a version bump (patch, minor, major)
  • Once committed it will create PR to be merged in
  • When the PR is merged, it will publish the new version to npm and update the CHANGELOG.md