nest 服务提供者

类注册

import { Module } from "@nestjs/common"

import { AppController } from "./app.controller"
import { AppService } from "./app.service"
import { MyService } from "./my/my.service"

@Module({
    imports: [],
    controllers: [AppController],
    providers: [AppService, MyService],
})
export class AppModule {}

使用：

export class AppController {
    constructor(private readonly MyService) {}
}

完整写法，可更改提供者名称

import { Module } from "@nestjs/common"

import { AppController } from "./app.controller"
import { AppService } from "./app.service"
import { MyService } from "./my/my.service"

@Module({
    imports: [],
    controllers: [AppController],
    providers: [
        AppService,
        {
            provide: "myService",
            useClass: MyService,
        },
    ],
})
export class AppModule {}

使用：

export class AppController {
    constructor(@Inject('myService') private readonly myService) {}
}

基本数据注册

import { Module } from "@nestjs/common"

import { AppController } from "./app.controller"
import { AppService } from "./app.service"

@Module({
    imports: [],
    controllers: [AppController],
    providers: [
        AppService,
        {
            provide: "config",
            useValue: { name: "wxw", author: "wxw" },
        },
    ],
})
export class AppModule {}

使用：

export class AppController {
    constructor(@Inject('config') private readonly config) {}
}

动态加载模块

实现根据不同的环境创建不同的服务，首先需要获取 env 环境变量

bash

pnpm add dotenv

创建 app.service.ts 和 my.service.ts

根据不同环境变量动态设置服务

import { Module } from "@nestjs/common"
import { config } from "dotenv"
import path from "node:path"

import { AppController } from "./app.controller"
import { AppService } from "./app.service"
import { MyService } from "./my/my.service"

config({ path: path.join(__dirname, "../.env") })

const appService = {
    provide: "appService",
    useClass: process.env.NODE_ENV === "development" ? AppService : MyService,
}
@Module({
    imports: [],
    controllers: [AppController],
    providers: [appService],
})
export class AppModule {}

自定义 DbModule 接入 typegoose

GitHub 仓库地址

主要代码实现

// db.module.ts
import { DynamicModule, Module, Provider } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { getModelForClass, mongoose } from '@typegoose/typegoose';

import { DbService } from './db.service';

interface ClassType { new (...args: any[]): any }

@Module({})
export class DbModule {
    static forRoot(envKey: string, options = {}): DynamicModule {
        const providers: Provider[] = [
            {
                provide: 'DB_CONNECT',
                inject: [ConfigService],
                useFactory: (configService: ConfigService) => {
                    const uri = configService.get<string>(envKey, 'MONGO_URI');
                    return mongoose.connect(uri, options);
                },
            },
        ];
        return {
            module: DbModule,
            providers,
            exports: providers,
            global: true,
        };
    }

    static forFeature(models: ClassType[]): DynamicModule {
        const providers = models.map((model) => {
            return {
                provide: model.name,
                useFactory: () => getModelForClass(model),
            } as Provider;
        });
        return {
            module: DbModule,
            providers,
            exports: providers,
            global: true,
        };
    }
}