nestjs-library/config

// in module
@Module({
    imports: [
        TypeOrmModule.forRootAsync({
            imports: [ConfigModule.forFeature(TypeORMConfigService)],
            useFactory: (typeORMConfigService: TypeORMConfigService) => typeORMConfigService,
            inject: [TypeORMConfigService],
        }),
    ],
})

// in service
const foo = this.testConfigService.foo;

Installation

# npm
npm install @nestjs-library/config

# yarn
yarn add @nestjs-library/config

# pnpm
pnpm add @nestjs-library/config

Usage

Step 1. Create a Config service

In @nestjs-library/config, each environment variable is managed by a provider. So, you should create a config service first.

We use class-transformer internally for transforming environment variables to Config Class. You can use decorators such as @Expose and @Type as your need.

// database-config.service.ts
import { Injectable } from '@nestjs/common';
import { AbstractConfigService } from '@nestjs-library/config';
import { Expose, Type } from 'class-transformer';

@Injectable()
export class DatabaseConfigService extends AbstractConfigService<DatabaseConfigService> {
    @Expose({ name: 'DATABASE_HOST' })
    host: string;

    @Expose({ name: 'DATABASE_PORT' })
    @Type(() => Number)
    port: number;

    @Expose({ name: 'DATABASE_PASSWORD' })
    password: string;
}

Step 2. Add decorator for validation and default value

You can use decorators from class-validator for validation and @Transform() decorator of class-transformer for providing default value.

// database-config.service.ts
import { Injectable } from '@nestjs/common';
import { AbstractConfigService } from '@nestjs-library/config';
import { Expose, Transform, Type } from 'class-transformer';
import { IsNotEmpty, IsPositive, IsString } from 'class-validator';

@Injectable()
export class DatabaseConfigService extends AbstractConfigService<DatabaseConfigService> {
    @Expose({ name: 'DATABASE_HOST' })
    @Transform(({ value }) => value ?? 'localhost')
    @IsString()
    @IsNotEmpty()
    host: string;

    @Expose({ name: 'DATABASE_PORT' })
    @Type(() => Number)
    @Transform(({ value }) => value ?? 5532)
    @IsPositive()
    port: number;

    @Expose({ name: 'DATABASE_PASSWORD' })
    @Transform(({ value }) => value ?? 'local')
    @IsString()
    @IsNotEmpty()
    password: string;
}

Step 3. Import Config module into your module

// test.module.ts
import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs-library/config';

import { DatabaseConfigService } from './database-config.service';
import { TestService } from './test.service';

@Module({
    imports: [ConfigModule.forFeature(DatabaseConfigService)],
    providers: [TestService],
    exports: [TestService],
})
export class TestModule {}

Step 4. Inject Config service where you need

// test.service.ts
import { Injectable } from '@nestjs/common';
import { DatabaseConfigService } from './database-config.service';

@Injectable()
export class TestService {
    constructor(private readonly databaseConfigService: DatabaseConfigService) {}

    getDatabaseConfig() {
        return this.databaseConfigService;
    }
}

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License

This library is licensed under the MIT License. See the LICENSE file for details.