injective-module

Injective module

This module developed to provide friendly syntaxes for dependency injections in TypeScript projects.

Contents

• Installation
• Usage
• Decorators

Installation

$ npm install injective-module

Usage

Basic usage

This example shows how to resolve the dependencies in the class without initializing the children's instances.

import { Injectable, Resolver } from 'injective-module'

@Injectable()
class FirstClass {
  say() {
    console.log('This is first class')
  }
}

@Injectable()
class SecondClass {
  say() {
    console.log('This is second class')
  }
}

class MainClass {
  constructor(
    public readonly firstClass: FirstClass,
    public readonly secondClass: SecondClass,
  )
}

const mainClass = Resolver.resolve<MainClass>(MainClass)
mainClass.firstClass.say() // This is first class
mainClass.secondClass.say() // This is second class

Usege with @Module

This example shows how to resolve the dependencies in the class with the @Module decorator.

import { Injectable, Module, Resolver, InstanceWrapper } from 'injective-module'

@Injectable()
class FirstPrivider {
  say() {
    console.log('This is first provider')
  }
}

@Injectable()
class SecondProvider {
  say() {
    console.log('This is second provider')
  }
}

class FirstService {
  constructor(
    public readonly firstPrivider: FirstPrivider,
    public readonly secondProvider: SecondProvider,
  )
}

@Module({
  providers: [FirstPrivider, SecondProvider, FirstService],
  exports: [FirstService],
})
export class FirstModule {}

@Module({
  imports: [FirstModule],
})
export class ApplicationModule extends InstanceWrapper<{
  firstModule: FirstModule
}> {
  onInit() {
    console.log(this.instances) // { firstModule: FirstModule }
    console.log(this.imports) // { firstModule: FirstModule }
    console.log(this.exports) // {}
  }
}

const applicationModule = Resolver.resolve<InstanceWrapper<{
  firstModule: FirstModule
}>>(ApplicationModule)

console.log(applicationModule.instances) // { firstModule: FirstModule }
console.log(applicationModule.imports) // { firstModule: FirstModule }
console.log(applicationModule.exports) // {}

Decorators

@Injectable

The @Injectable() decorator used for defining the contructors implementation metadata and getting it in application via Reflect

Example:

@Injectable()
class InjectableClass {
  say() {
    console.log('Hi!')
  }
}

@Injectable()
class MainClass {
  constructor(private injectableClass: InjectableClass) { }
}

const mainClass = Resolver.resolve<MainClass>(MainClass)
mainClass.injectableClass.say() // Hi!

@Module

The @Module() decorator used to define imports, providers and exports for decorated class. Those instances will be available in a decorated class with automatically resolved dependencies. This decorator should be used along with the InstanceWrapper abstract class, this class allowed to retrieve interesting instances from Reflect metadata which is dependent on the decorated class.

key	description	default
imports	This key used for importing the other modules and adding the exported instances to the decorated class.	[]
providers	This key used to resolving the dependencies inside the module.	[]
exports	Using for sharing instances between modules.	[]

Example:

@Injectable()
class FirstClass {
  say() {
    console.log('Hi first class!')
  }
}

@Injectable()
class SecondClass {
    say() {
    console.log('Hi second class!')
  }
}

@Injectable()
class ThirdClass {
  constructor(
    private firstClass: FirstClass,
    private secondClass: SecondClass,
  ) { }
}

@Module({
  providers: [FirstClass, SecondClass, ThirdClass],
  exports: [ThirdClass]
})
class FirstModule {}

@Module({
  imports: [FirstModule]
})
class SecondModule extends InstanceWrapper<{
  firstModule: FirstModule
}> {
  onInit() {
    this.instances.firstModule.firstClass.say() // Hi first class!
    this.instances.firstModule.secondClass.say() // Hi second class!
  }
}

const secondModule = Resolver.resolve<InstanceWrapper<{
  firstModule: FirstModule
}>>(SecondModule)

// Usage outside the class
secondModule.instances.firstModule.firstClass.say() // Hi first class!
secondModule.instances.firstModule.secondClass.say() // Hi second class!