DEV Community πŸ‘©β€πŸ’»πŸ‘¨β€πŸ’»

DEV Community πŸ‘©β€πŸ’»πŸ‘¨β€πŸ’» is a community of 963,673 amazing developers

We're a place where coders share, stay up-to-date and grow their careers.

Create account Log in
Cover image for Using existing services in a custom medusa service
Chris Bongers
Chris Bongers

Posted on • Originally published at daily-dev-tips.com

Using existing services in a custom medusa service

In the previous article, we had an introduction to creating our very first custom medusa service.

I wanted to expand on that and show you how we can use this custom service for other services.
This is not limited to the medusa ones. You can even load your custom services this way.

For this article, we'll use the translation service as our base. Inside we'll look at injecting the product service so we can translate products.

Using other services inside a custom service

The main file will stay the same. As we already extend the TransactionBaseService we can use the constructor and assign services via this constructor.

Let's look at how we can import the product service.

class TranslateService extends TransactionBaseService {
  productService;

  constructor({ productService }) {
    super();
    this.productService = productService;
  }
}
Enter fullscreen mode Exit fullscreen mode

This will give us access to the product service.
Let's create a translateProduct function. This function will take a product ID. With this ID it can fetch the product and return the title.
(In a real-world example, we would get a translation from another table)

translateProduct = async (productId, locale) => {
  const product = await this.productService.retrieve(productId);
  // Here we would add our translation
  return product.title;
};
Enter fullscreen mode Exit fullscreen mode

Let's modify our endpoint so we can test out if it works.

router.get('/store/title', (req, res) => {
  const translateService = req.scope.resolve('translateService');
  translateService
    .translateProduct('prod_01GCKNHT1KPGBK1JR2MK7JC6KY', 'en')
    .then((title) => {
      res.json({ title });
    });
});
Enter fullscreen mode Exit fullscreen mode

You should see the title returned if you re-run your server and query this route.

Note: make sure to change the ID to a product you have in your database

Product service query in medusa custom service

Using a custom service

Let's say we want to create yet another custom service we call TestService.

Inside this service, we want to use our custom translate service.
We can easily use the same approach to use.

import { TransactionBaseService } from '@medusajs/medusa';

class TestService extends TransactionBaseService {
  translateService;

  constructor({ translateService }) {
    super();
    this.translateService = translateService;
  }

  test(msg, locale) {
    return this.translateService.translate(msg, locale);
  }
}

export default TestService;
Enter fullscreen mode Exit fullscreen mode

So nothing special here. We port the existing translate function into this test function.

We can then use it as such:

router.get('/store/title', (req, res) => {
  const testService = req.scope.resolve('testService');
  const title = testService.test('title', 'nl');
  res.json({ title });
});
Enter fullscreen mode Exit fullscreen mode

This is merely an example of how you can use your custom services inside another custom service.

Thank you for reading, and let's connect!

Thank you for reading my blog. Feel free to subscribe to my email newsletter and connect on Facebook or Twitter

Top comments (1)

This post blew up on DEV in 2020:

js visualized

πŸš€βš™οΈ JavaScript Visualized: the JavaScript Engine

As JavaScript devs, we usually don't have to deal with compilers ourselves. However, it's definitely good to know the basics of the JavaScript engine and see how it handles our human-friendly JS code, and turns it into something machines understand! πŸ₯³

Happy coding!