Express: Using Decorators in Express

[mohammedzamakhan]

I wanted Decorators to be part of Express restful API system, where you can define the url, method etc using decorators. This exist in Java Spring Framework like

@RestController
public class GreetingController {

    private static final String template = "Hello, %s!";
    private final AtomicLong counter = new AtomicLong();

    @RequestMapping("/greeting")
    public Greeting greeting(@RequestParam(value="name", defaultValue="World") String name) {
        return new Greeting(counter.incrementAndGet(),
                            String.format(template, name));
    }
}

ref: https://spring.io/guides/gs/rest-service/

so in Express this

app.get('/greeting', function (req, res) {
  res.send('Hello World!');
});

could convert to

@RestController()
class GreetingController() {
    @Request('/greeting')
    greeting(req, res) {
       res.send('Hello World!');
    }
}

This way a lot of Java Developers would be interested in NodeJS and Express environment and MEAN 2 would be great because Angular 2 also uses decorators 😄

[dougwilson]

Huh, I didn't even realize decorators have been added to JavaScript at all. What would Express need to do to support them, if it hypothetically wanted to?

[Twipped]

They haven't been, it's still an experimental addition that only exists in babel.

[LinusU]

Decorators is still in stage 2 which means that they are not yet a part of the language...

[dougwilson]

Ah, thanks guys :) So regardless of the merits of even handing decorators in Express, if it's not even a part of core JavaScript, I don't think now is the right time to support them.

FWIW, I did a quick Google and found https://www.npmjs.com/package/express-decorators which may do what you're looking for @mohammedzamakhan

[Twipped]

@mohammedzamakhan You could do it now, tho not with the syntax you've added here.

var router = express.Router();
function Request (method, path) {
  return function (fn) {
    router[method.toLowerCase()](path, fn);
  }
}

@Request('GET', '/greeting')
function greeting (req, res) {}

I'm not sure it's really up to express to add that support, it's more suited to a third party lib.