@epiijs/inject

A simple dependency injector.

Install

npm i @epiijs/inject --save

Usage

import { createInjector } from '@epiijs/inject';

const injector = createInjector();

injector.provide('UserService', () => {
  return {
    connect: () => {},
    dispose: () => {}
  };
});

const service = injector.service('UserService');
service.connect();

injector.dispose();

API

createInjector

import { createInjector } from '@epiijs/inject';

const injector = createInjector();

injector.provide

injector.provide can accept any service values or service factory functions.

export interface IUserService {}

// provide instance as service
export const userService: IUserService = {};

// provide factory function as service
export function createUserService(): IUserService {
  const userService: IUserService = {};
  return userService;
}

injector.provide('UserService', userService);
// injector.dispose('UserService');
injector.provide('UserService', createUserService);

injector.inherit

injector.inherit can be attached with another injector. Current injector will try to find services from inherited injector if nothing found from itself.

const injector = createInjector();

const anotherInjector = createInjector();
anotherInjector.provide('UserService', {});
injector.inherit(anotherInjector);

const service = injector.service('UserService');

injector.service

injector.service can find service by name, create service instance and return it.

const service = injector.service('UserService');

Also you can use the first argument of service factory function as service locator to find other services.

injector.provide('PlanService', (services) => {
  const userService = service.UserService;
  return { user: userService, plan: undefined };
});

Actually injector.serivce() will return a service locator proxy.

injector.dispose

injector.dispose will dispose specified service by name or all instances and clear all providers.

export const userService: IUserService = {
  // you can use Symbol.dispose method to dispose
  // [Symbol.dispose]: () => {
  //   console.log('disposed');
  // },

  // also you can use 'dispose' method to dispose
  dispose: () => {
    console.log('disposed if Symbol.dispose method not defined');
  }
};

injector.provide('UserService', userService);

injector.dispose('UserService');
injector.dispose();

// console output: disposed