🚀 Nestjs BareBones Controllers & ReqObjects

🧩 features

1. typescript(disciplined)
2. oops(SOLID principles)
3. scalable/testable/loosely coupled production grade architecture boilerplate setup

👶 steps(understanding the blueprint)

• npm i -g @nestjs/cli

              # cmd line
              nest -v
  
              # config your nest backend
              nest new nest-basics-api
  
              # choices
              npm or yarn or pnpm
  

**app.module.ts is the root of the api**

**everything is imported inside app.module and then this is exported and bootstrapped inside main.ts to create the nest backend**

🔧 building the api

1. 📩 Controllers

**Handles incoming request from client and sends back response**

** ✏ never write the buisness logic inside the controllers**

• In nest we define controllers via decorators that provide meta data about what functionality a particular code block will have

**the access decorators import @nestjs/common**

            Controllers
                    |- student.controller.ts

            # student.controller.ts
            import { Controller } from @nestjs/common

            # Controller will tell nest that this is a controller based class

            @Controller('students')
            class StudentController {

            }

**every single route inside studentController is going to start as /students**

**it can be specified with a @Get() decorator that this is a get request**

            @Get()
            getStudents(){
                // return all students data
            }

**make sure to import the student.controller.ts inside the app.module.ts**

✔ running dev server first time

                npm run start:dev
                # make sure the main.ts is just under the src directory

• nested routes like /students/:studentId

              @Get('/:studentId')
              getStudentById(){
                  return "Get Student By Id"
              }
  

🐱‍🚀🐱‍🚀🐱‍🚀TIRED OF REPETATIVE CONTROLLERS SETUP🐱‍🚀🐱‍🚀🐱‍🚀

Creating controllers through nestcli 🐱‍👤

• https://docs.nestjs.com/controllers

              nest g controller <controllerName> --no-spec
              # only add --no-spec flag if you dont need unit test file for this controller
  

best practice is to put similir prefix routes in seprate controller

                # to run tests
                npm run test:watch

2. Request Objects (extracting pieces of info from request like params)

make use @param () decorator in Nest for GET

                # student object in student ID
                @Get('/:studentId')
                getStudentById(
                    @Param () params: {studentId: string}
                ) {
                    console.log(params)
                    return 'Get Student By Id';
                }

• further it can be simplified while the required params can be destructured at the time of decorator defination

              # @Param('destructuredObjectFromParams')
              @Param ('studentId') studentId: string
              console.log(studentId)
  

make use @Body () decorator in Nest for POST

                @Post()
                createStudent(
                    @Body() body
                ) {
                    return `Create's New Student with details\n ${JSON.stringify(body)}`;
                }

use @Body & @Parma together for PUT

                @Put('/:studentId')
                updateStudentById(
                    @Param('studentId') studentId: string,
                    @Body() body
                ) {
                    return `Update's\n student id: ${JSON.stringify(studentId)}\n with new data ${body}`;
                }

Further their are @Query, @Session, @Next and @ip() that can be useful refer- https://docs.nestjs.com/controllers#request-object

                @Put('/:studentId')
                updateTeacherOfStudentById(
                    @Param('teachersId') teachersId: string,
                    @Param('studentId') studentId: string,
                    @Ip() clientIP: string 
                ) {
                    return `clientIP: ${clientIP}\nUpdate's Teacher with ID: ${teachersId}\n Associated To Student With Id: ${studentId}`;
                }

📚 refferences

• codeSnippet : https://github.com/Jasmeet-1998/TNG/tree/master/nest-basics-api
• ⛑ https://docs.nestjs.com/
• 🧪 https://docs.nestjs.com/fundamentals/testing