nestjs study

nestjs request

命令行工具 nest cli

全局安装命令行工具
npm i -g @nestjs/cli
安装后可以使用 nest 命令

或者使用
npx @nestjs/cli@latest
替代nest 命令


模拟命令，可以看到命令生成的文件，但不会真正生成
--dry-run

eg:
nest g module user --dry-run


CRUD generator
可以生成 module, controller, service, dto etc
nest g resource

eg:
nest g resource users


To avoid generating test files, you can pass the --no-spec flag, as follows: 
nest g resource users --no-spec



npx @nestjs/cli new project-name

使用装饰器获取 request 的param， body， query

@Controller('users')
export class UsersController {
  @Get()
  getUsers(@Query('sortBy') sortBy: string) {
    console.log(sortBy); //get asc; from url /users?sortBy=asc
    return {
      a: 'a',
    };
  }

  @Post()
  createUser(@Req() request: Request, @Res() response: Response) {
    console.log(request);

    const body = request.body;
    console.log(body); //{ name: 'xiaomig', password: '123456' } get json obj send from frontend

    const query = request.query;
    console.log(query); // get { att: 'value' } from url like /users?att=value

    response.send('created');
  }

  @Post('create')
  creat(@Body() userData: createUserDto) {
    console.log(userData); //decorator method get request.body { name: 'xiaomig', password: '123456' } get json obj send from frontend
    return {};
  }

  // param route should be placed beneath the actually named routed like create route above,
  // or you cannot use the create route, because it is interceptted by param route :id and treated with it.
  @Post(':id')
  createUsers(@Req() request: Request, @Res() response: Response) {
    //
    const params = request.params;
    console.log(params); //get { id: '34' } from url like /users/34
    response.send('createUsers');
  }

  @Get(':id')
  getOneUser(@Param('id') id: string) {
    //get parameter using @Param
    console.log(id); //get 10 from url like /users/10
    return { id };
  }

  @Get(':userid/:postid')
  getUserPost(
    @Param('userid') userid: string,
    @Param('postid') postid: string,
    @Body() postdata: createUserDto,
  ) {
    //get parameter using @Param
    console.log(userid); //
    console.log(postid); //get 10 and 100 from url like /users/10/100
    // get method can also get the json obj send from frontend/
    // but do not suggest do that data send by get method is limited to size 2kb-8kb,and data transmit is not encripted
    console.log(postdata);
    return { userid, postid };
  }





  // :id 带冒号的是路由变量， status 不带: 是固定字符串
  // 如Patch路由 /525b14d0-3b46-45d9-8e64-0c3846611430/status
  @Patch('/:id/status')
  updateTaskStatus(
    @Param('id') id: string,
    @Body ('status') status: TaskStatus
  ): Task{
    return this.taskService.updateTaskStatus(id, status)
  }


}

graphql 的 resolover 中定义 参数为可选参数的方法

  @Query(() => [Hotel], { nullable: true })
  async hotels(
    @Args('paginationArg') pagination?: PaginationArg,
  ): Promise<PaginationedHotel> {
    return await this.hotelsService.findAll(pagination);
  }


如参数 paginationArg 默认是必填的，加上{ nullable: true }这样参数 paginationArg 就是可选的
@Args('paginationArg', { nullable: true }) pagination: PaginationArg,

@Args('filters', { nullable: true }) filters: ReservationFiltersInput,

Graphql Object types

@ObjectType()
export class PaginationedHotel {
  @Field(() => [Hotel], { nullable: true })
  result: Hotel[];

  @Field(() => Pagination, { nullable: true })
  pagination: Pagination;
}

// 注意 @Field(() => [Hotel], { nullable: true }) 是针对graphql 的定义,graphql 数组的写法[hotel]
// result: Hotel[]; 是针对 typescript 类型定义, typescript 数组一般这样写 Hotel[]

mongoose schema Options

参考 https://mongoosejs.com/docs/schematypes.html#schematype-options

@Prop({ required: true })
name: string;


// 设置默认值
@Prop({ default: "some value or function" })
name: string;

@Prop({
  type: mongoose.Schema.Types.ObjectId,
  ref: 'Reservation',
  default: [],
})
reservations: Reservation[];


// 可选属性/字段
@Prop({
  default: RESERVATION_STATUS.START,
})
status?: string;

log 日志

常用日志module

morgan

HTTP request logger middleware for node.js

:method :url :status :response-time ms - :res[content-length]

Winston - A logger for just about everything.

Nodejs 环境下最常用的logger

pino - super fast, all natural json logger

nestjs lifecycle

环境变量

If a module configuration depends on the environment variables, and these variables are loaded from the .env file, you can use the ConfigModule.envVariablesLoaded hook to ensure that the file was loaded before interacting with the process.env object, see the following example:

tasks.module.ts

import { Module } from '@nestjs/common';
import { TasksController } from './tasks.controller';
import { ConfigModule } from '@nestjs/config';



// 这时为 undefined： process.env.PORT
console.log(`${process.env.PORT} =====TASK MODULE`)

export async function getStorageModule() {
  await ConfigModule.envVariablesLoaded;

  // 这时可以取到process.env.PORT的值，如10000 
  console.log(`${process.env.PORT} =====TASK MODULE`)
}

getStorageModule()

@Module({
  controllers: [TasksController]
})
export class TasksModule {}

typeorm example

return await this.eventRepository.find({
  where:{
    id: MoreThan(1),
    when: MoreThan(new Date("2021-02-12T13:00:00"))
  },
  take: 2, // limit
  skip: 1, // offset
  order:{
    id: 'DESC',
  }
})


//multiple or condition

where:[
  {
    id: MoreThan(1),
    when: MoreThan(new Date("2021-02-12T13:00:00"))
  },
  {
    description: Like('%meet%')
  }
],

// specify returned fields
select:["id", "address", "description"],