@rnw-community/nestjs-typed-config v0.67.0

NestJS Typed config

NestJS typed configuration with full TypeScript support.

Installation

Install additional peer dependencies:

• @nestjs/config
• joi

Configuration

• Create enum with names for all the required environment variable names, interface with type for every environment variable and validation schema using joi.

export enum EnvironmentVariablesEnum {
    POSTGRES_USERNAME = 'POSTGRES_USERNAME',
    POSTGRES_PASSWORD = 'POSTGRES_PASSWORD',
    POSTGRES_HOST = 'POSTGRES_HOST',
}

export interface EnvironmentVariablesInterface {
    [EnvironmentVariablesEnum.POSTGRES_USERNAME]: string;
    [EnvironmentVariablesEnum.POSTGRES_PASSWORD]: string;
    [EnvironmentVariablesEnum.POSTGRES_HOST]: string;
}

import Joi from 'joi';

export const environmentVariablesValidationSchema = Joi.object({
    [EnvironmentVariablesEnum.POSTGRES_USERNAME]: Joi.string().required(),
    [EnvironmentVariablesEnum.POSTGRES_PASSWORD]: Joi.string().required(),
    [EnvironmentVariablesEnum.POSTGRES_HOST]: Joi.string().required(),
});

• Create config module and service for NestJS DI, this module and service should be used in the project:

import { Inject, Injectable } from '@nestjs/common';

import { NestJSTypedConfigModule } from '@rnw-community/nestjs-typed-config';

const [BaseConfigModule, BaseConfigService] = NestJSTypedConfigModule.create<
    EnvironmentVariablesEnum,
    EnvironmentVariablesInterface
>(environmentVariablesValidationSchema);

@Injectable()
export class ConfigService extends BaseConfigService {}

@Module({
    imports: [BaseConfigModule],
    providers: [ConfigService],
    exports: [ConfigService],
})
export class ConfigModule {}

Usage

import { ConfigService } from './config.module.ts';

@Injectable()
class DomainService {
    private readonly postgresPassword: string;

    constructor(private readonly config: ConfigService) {
        this.postgresPassword = config.get(EnvironmentVariablesEnum.POSTGRES_PASSWORD);
    }

    // ...
}

Reading values from files

To read an environment variable from file, the environment variable name should end with _FILE:

export enum EnvironmentVariablesEnum {
    POSTGRES_PASSWORD_FILE = 'POSTGRES_PASSWORD_FILE',
}

Value of that environment variable should be a path to the file:

echo $POSTGRES_PASSWORD_FILE
/secrets/postgres_pwd

License

This library is licensed under The MIT License.