Image processing with Jimp. Optional methods parameters.

Kuba — Tue, 25 Dec 2018 18:08:35 +0000

Hi guys.

I'm working on some kind of cloud image hosting and processing. I do use Jimp, which is great and works like a charm.

Jimp's giving a lot of cool image processing methods, such as resizing, scaling and so on. You can chain methods to apply multiple effects, f.ex.:

Jimp.read('image/path')
 .then(image => {
     image
        .resize()
        .scale()
        .grayscale()
 })
 ....

What do I want to achieve

I want to process images in a fly. For example, I do have an URL:

[...].images.io/i/image-uuid?list=a&of=b&params=c

These params can be f.ex. width, height, scale, rotate etc.

For now I can manipulate image by giving one specific parameter f.ex.

[...].images.io/i/image-uuid?scale=0.5

and it's works - it's scaling image.

But I want to have opportunity to use bunch of options in one request f.ex.:
[...].images.io/i/image-uuid?scale=0.5&filter=grayscale&rotate=80

and I do not know how make it work. For now - Jimp offers more than 30 methods what gives us bunch of combinations so simple switch-case won't work. ;)

Basing on documentation, there is no thing such as optional params, and you cannot pass nulls or undefined as a method params.

Any ideas how can i overcome this? :)

Happy Holidays everyone!

NodeJS - Unit Tests - testing without hitting database. Confusings.

Kuba — Tue, 21 Aug 2018 18:04:59 +0000

I'm trying to learn TDD approach. I have no troubles with a simple code where I do not need to mock or stub any external methods or dependencies, but where it comes to write tests for some code that based on database I'm getting feel a little bit confused.

It's clear to me, that the unit tests should tests a small piece of code that do not depends on other services and so on.

Lets assume that I want to unit test a creating user feature.

I know that in TDD I should start by writing failing test - but I don't know how it should look like. ;)

So, here is the example, simplified service:

class UserService {

  // typeORM repository
  constructor(userRepository: Repository<User>) {}

  async createAccount(user) {

   // Saves user to database and return created entity object
   return await this.userRepository.save(user);
  } 

}

By now I'm able to spy on method and check if is called properly, with correct params etc. (I'm using Jest)

it('Should create a user.', async () => {

  const USER = {
   email: 'test@user.com',
   username: 'user',
   password: 'user',   
  };

  const SPY = jest.fn(() => USER);
  jest
    .spyOn(userService, 'createAccount')
    .mockImplementation(() => SPY(USER));

  await userService.createAccount(USER);
  expect(SPY).toHaveBeenCalledTimes(1);
  expect(SPY).toHaveBeenCalledWith(USER);

});

And here comes my main question. How should the failing tests looks like? I mean if I stub createAccount method like I did above, it will always pass. Even if the method is empty. It's only requires method declaration. Should I mock repository methods that returns what typeORM is supposed to returns? e.g.:

const REPOSITORY_MOCK = jest.fn(() => ({
    save: jest.fn().mockImplementation((user) => user),
}));

I think that I missed something. :/

Or Am I try to over complicate it and I should only testing if the method is calling properly? And the whole database related stuff should be test by integration tests where I'm able to work on database?

I'm looking forward any kind of help. Thank you in advance.

Cheers, Kuba.

DEV Community: Kuba

Image processing with Jimp. Optional methods parameters.

What do I want to achieve

NodeJS - Unit Tests - testing without hitting database. Confusings.