honkjs/injector

Injects services into functions passed to honk. Very similar functionality to redux-thunk.

import Honk from '@honkjs/honk';
import injector from '@honkjs/injector';
import api from 'mycoolapi';

const honk = new Honk()
  // add injector to the middleware pipeline
  .use(injector({ api })).honk;

function getSomething(name) {
  return function({ api }) {
    // returns a promise
    return api.fetchSomething(name);
  };
}

honk(getSomething('bob')).then((results) => console.log(results));

Injector always returns the results of the function passed in.

"Dependency injection" is handled using js object deconstruction.

// no deconstruction
function boringThunk(name) {
  return function(services) {
    return services.api.getSomething(name);
  };
}

// deconstructed
function coolThunk(name) {
  return function({ api }) {
    return api.getSomething(name);
  };
}

honk(boringThunk('Bob'));
honk(coolThunk('George'));

There is no dependency resolution, or anything fancy like that. Injector is built with the simple goal of allowing you to easily access application services from anywhere honk is available.

Type safety

If you're using typescript, you likely want some type safety on the services object. There are a couple ways to achieve this. Which way you use is totally a matter of preference.

Union type

type MyHonkAppServices = {
  api: MyApi;
} & IHonkServices;

// this creates a new type combining the IHonkServices with your own
// { api: MyApi, honk: IHonk }

function coolThunk(name) {
  return function({ api }: MyHonkAppServices) {
    return api.getSomething(name);
  };
}

Declaration merging

Similar to how IHonk can be overloaded, you can use declaration merging.

declare module '@honkjs/injector' {
  interface IHonkServices {
    api: MyApi;
  }
}

// The standard IHonkServices type will now be:
// { api: MyApi, honk: IHonk }

function coolThunk(name) {
  return function({ api }: IHonkServices) {
    return api.getSomething(name);
  };
}

Manually

type MyHonkAppServices = {
  honk: IHonk;
  api: MyApi;
}

function coolThunk(name) {
  return function({ api }: MyHonkAppServices) {
    return api.getSomething(name);
  };
}