sahilrajput03

learn-nestjs

REPOSITORY - https://github.com/sahilrajput03/learn-nestjs/

• Reference project using nestjs: Click here
• Fixing circular dependency: Official Docs: Click here
• Testing with NestJS: Click here
• Writing tests with nestjs is awesome:
• Declartive Cron Jobs with NestJS: Click here

global interceptors in nestjs:

Interceptors

NestJs: Click here

Source: Click here

In file app.module.ts, you can add a suitable provider like that:

USAGE:

Interceptors can be nested in this way I guess:

interceptors in nestjs:

• Awesome Documemntation: Click here
• Read my tap and catchError info @ my learn-rxjs.md
• Attach/get data of request object: Click here-stackoverflow

http requests, and jest mocking:

    it.only('cool testing', async () => {
      jest.spyOn(httpService, 'get')
      .mockImplementation(() => of({ data: 100, status: 202, statusText: '', headers: {}, config: {} }))
      .mockImplementationOnce(() => of({
        data: 101,
        status: 202,
        statusText: '',
        headers: {},
        config: {},
      }))
      .mockImplementationOnce(() => of({
        data: 102,
        status: 202,
        statusText: '',
        headers: {},
        config: {},
      }));

      const { data: data1 } = await lastValueFrom(httpService.get('/'));
      console.log({ data1 }); // 101

      const { data: data2 } = await lastValueFrom(httpService.get('/'));
      console.log({ data2 }); // 102

      const { data: data3 } = await lastValueFrom(httpService.get('/'));
      console.log({ data3 }); // 100

      const { data: data4 } = await lastValueFrom(httpService.get('/'));
      console.log({ data4 }); // 100
      expect(1).toBe(1);
    });

Other Cool things:

• Thats how you can use a model in specification file (test file):

• Using multiple gateways create different socket servers?

  tldr; NO. They use same server instance if they have same ports. Source: Click here

  

• Adding service as dependency injection to the controller. So this simply means that nestjs will automatically instantiate the service class for us.

• Using params:

  

• Passing route path (as string) to controller decorator.

  

• nest generate service users:

  

• nest generate controller users:

  

• nest generate module users:

  

• app.module.ts:

  

• These decorators optionally can have string as first argument to define the path of the api handling of each of them.

  

  

• Thats where the nestjs app starts:

  

• How three layer architecture works for backends? Source (quite extensive article {not at all for begineers}).

  

Swagger Usage

• We can create new sections in the swagger docs by assigning tags to a controller like that:

  

  and it’ll reflect like: