hymn-di

Simple dependency injection solution for React.

The base of this project stems from react-simple-di. It is not intended to be backwards-compatible, as it will introduce breaking updates & new features.

Differences from react-simple-di

• Ability to module-namespace actions
  • See https://github.com/kadirahq/mantra/issues/199 for details

Installation

npm i hymn-di

Intro

In hymn-di, we've two types of dependencies, they are:

1. context - These are usually, configurations, models and client for different remote data solutions.
2. actions - Actions are simple functions which used to perform business logic with the help of the above context.

Every action will receive the context as it's first argument and actions as it's second argument.

Injecting Dependencies

First, we need to inject dependencies to a root level React component. Mostly, this will be the main layout component of our app.

Here are our dependencies:

const context = {
    DB,
    Router,
    appName: 'My Blog'
};

const actions = {
    posts: {
        create({DB, Router}, title, content) {
            const id = String(Math.random());
            DB.createPost(id, title, content);
            Router.go(`/post/${id}`);
        }
    }
};

First we've defined our context. Then, we have our actions. Here actions must follow a structure like mentioned above.

Let's inject our dependencies:

import { injectDeps } from 'hymn-di';
import Layout from './layout.jsx';

// Above mentioned actions and context are defined here.

const LayoutWithDeps = injectDeps(context, actions)(Layout);

Now you can use LayoutWithDeps anywhere in your app.

Using Dependencies

Any component rendered inside LayoutWithDeps can access both context and actions.

When using dependencies it will compose a new React component and pass dependencies via props to the original component.

First let's create our UI component. Here it will expect dependencies to come via props appName and createPost.

class CreatePost extends React.Component {
    render() {
        const {appName} = this.props;
        return (
            <div>
                Create a blog post on app: ${appName}. <br/>
                <button onClick={this.create.bind(this)}>Create Now</button>
            </div>
        );
    }

    create() {
        const {createPost} = this.props;
        createPost('My Blog Title', 'Some Content');
    }
}

So, let's use dependencies:

const { useDeps } from 'hymn-di';

// Assume above mentioned CreatePost react component is
// defined here.

const depsToPropsMapper = (context, actions) => ({
    appName: context.appName,
    createPost: actions.posts.create
});

const CreatePostWithDeps = useDeps(depsToPropsMapper)(CreatePost);

That's it.

Note: Here when calling the actions.posts.create action, you don't need to provide the context as the first argument. It'll handle by hymn-di.

Default Mapper

If you didn't provide a mapper function, useDeps will use a default mapper function will allows you to get context and props directly. Here's that default mapper:

const mapper = (context, actions) => ({
    context: () => context,
    actions: () => actions
});