CODEWITHSUNDEEP
jestjsmockingnestjs
paranoid
paranoid

Reputation: 7105

nestjs mock i18n and request in jest service

I have a controller like this

async create(@Body() dto: myDTO,@Req() request, @I18n() i18n?: I18nContext): Promise<MyEntity> 
{
   return this.Myservice.create(dto, request, i18n);
}

and service like this:

async create(dto: CreateApplicationDTO,  request?, i18n?): Promise<Application> {
     const MyEntity= this.repository.create(dto);
     request.message = i18n.t('common.added_successful');
     return this.repository.save(MyEntity);
}

and service.spec file this :

it('check number of created applications', async () => {
     await service.create(myDto);
     expect(await service.findAll()).toHaveLength(1);
});

When I start test show me this error

TypeError: Cannot set properties of undefined (setting 'message')

  41 |             return this.repository.save(newApplication);
  42 |         } catch (e) {
> 43 |             return request.message = e.message;
     |                                   ^
  44 |         }
  45 |
  46 |     }

I know I should send request and i18n to service but I don't know how mock them and send them to service in my spec file

Upvotes: 0

Views: 1551

Answers (1)

Jay McDoniel
Jay McDoniel

Reputation: 70490

You've set request to be optional but set a property on it regardless if it is populated or not. You need to make sure that request has a value before you try to assign to it. For simplicity sake, because you don't give it a type, it could just be {} and then {}.message = will be valid.

As for i18n in your create method you use the object method t so you need the mock to have a t method. Something like { t: jest.fn(() => 'some value') } should be enough to get the test going with a mock.

Having stronger typings will help you though, even if it means it is harder to make mocks. You could use a tool like @golevelup/ts-jest can be used to create full mocks off of types alone

Upvotes: 1

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