injex-express-plugin

Turn your Express application into a dependency-injection ballet using Injex

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Why should you use this Injex plugin?

When working with Express applications, one of the hassles is to config all your application routes and route handlers. This plugin helps organize your application by using controllers and decorators, each controller has it's own route handlers for a specific application domain.

Install

Install Injex Express Plugin using NPM or Yarn:

npm install --save injex-express-plugin

Or

yarn add injex-express-plugin

Basic usage

const container = Injex.create({
    
    rootDirs: [
        "./controllers",
        "./managers",
        "./services",
    ],
 
    ...more injex config...
 
    plugins: [
        ...more plugins...
 
        new InjexExpressPlugin({
            // plugin configurations...
        })
    ]
})

Example Controller:

@define()
@controller()
export class ProductsController {
 
    @inject() private productsManager: ProductsManager;
 
    @get("/products")
    public renderAllProductsPage(req, res) {
        res.render("products", {});
    }
 
    @get("/products/:productId")
    public async renderProductPage(req, res) {
        const product = await this.productsManager.getProductById(req.params.productId);
 
        res.render("product", {
            product 
        });
    }
 
    @post("/products/create")
    public async createProduct(req, res) {
        const newProduct = await this.productsManager.create(req.body);
 
        res.redirect(`/products/${newProduct.id}`);
    }
}

Check out the example folder for a more detailed usage.

Configurations

You can use the following plugin configurations:

app: Application

• Pass in an express application instance if you already configured one.
  Default: null

createAppCallback: CreateAppCallback

• When no express application provided to the app config, the express application will be created internally by the plugin, this callback will be called with the application instance so you can complete the app configurations.
  Default: null

  For example:

  const PORT = process.env.PORT || 8080;
   
  const container = Injex.create({
      
      ...injex config...
   
      plugins: [
          ...more plugins...
   
          new InjexExpressPlugin({
              createAppCallback: function(app) {
                  // set app middlewares and/or any other configurations here...
                  app.listen(PORT, () => console.log(`App is running on ${PORT}...`));
              }
          })
      ]
  });

Decorators

@controller()

• Define a module as a controller.
  User this decorator on your controller class for example:

@get([path]), @post([path]), @post([path]), @patch([path]), @put([path]), @del([path])

• Binds a controller method into Express application route.

Controller example:

@define()
@controller()
export class HomeController {
 
    @get("/")
    public renderRoot(req, res) {
 
    }
 
    @get("/product/:id")
    public renderProduct(req, res) {
 
    }
 
    @post("/product/create")
    public createProduct(req, res) {
 
    }
}

Is the same as the traditional express way:

app.get("/", function(req, res) {
 
});
 
app.get("/product/:id", function(req, res) {
    
});
 
app.post("/product/create", function(req, res) {
    
});

The difference is that with Injex, you can inject dependencies into your controller.
Another difference is the use of the @singleton() decorator, as you can see from the example above, the HomeController is defined without it, it means that you will get a "fresh" HomeController instance for each request, you can call it a session controller. When using the @singleton() decorator on a controller class, you get the same controller instance for each client request.

For example:

@define()
@singleton()
@controller()
export class HomeController {
 
    private visitors: number;
 
    constructor() {
        this.visitors = 0;
    }
 
    @get("/")
    public render(req, res) {
        res.send(`<h1>This page visited ${++this.visitors} times!</h1>`);
    }
}

And without the @singleton() decorator:

@define()
@controller()
export class HomeController {
 
    private visitors: number;
 
    constructor() {
        this.visitors = 0;
    }
 
    @get("/")
    public render(req, res) {
        res.send(`<h1>${++this.visitors} === 1</h1>`);
    }
}

Check out the example folder for a more detailed usage.

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Having an issue? A feature idea? Want to contribute?

Feel free to open an issue or create a pull request