NestJS using Environment Variable - node.js

Question

I have my environment variable in the root of the director and the following config files to import as a module.
/config/config.service.ts
// NPM Packages
import * as dotenv from 'dotenv';
import * as fs from 'fs';
import * as Joi from '#hapi/joi';
export type EnvConfig = Record<string, string>;
export class ConfigService {
private readonly envConfig: EnvConfig;
constructor(filePath: string) {
const config = dotenv.parse(fs.readFileSync(filePath));
this.envConfig = this.validateInput(config);
}
/**
* Ensures all needed variables are set,
* and returns the validated JavaScript object
* including the applied default values.
*/
private validateInput(envConfig: EnvConfig): EnvConfig {
const envVarsSchema: Joi.ObjectSchema = Joi.object({
NODE_ENV: Joi.string()
.valid('development', 'production', 'test', 'provision')
.default('development'),
PORT: Joi.number().default(3000),
MONGO_URI: Joi.required(),
API_AUTH_ENABLED: Joi.boolean().required(),
IS_AUTH_ENABLED: Joi.boolean().required(),
JWT_SECRET: Joi.required(),
JWT_EXPIRE: Joi.required(),
JWT_COOKIE_EXPIRE: Joi.required(),
});
const { error, value: validatedEnvConfig } = envVarsSchema.validate(
envConfig,
);
if (error) {
throw new Error(`Config validation error: ${error.message}`);
}
return validatedEnvConfig;
}
get(key: string): string {
return this.envConfig[key];
}
}
/config/config.module.ts
// Core Packages
import { Module } from '#nestjs/common';
// Custom Packages
import { ConfigService } from './config.service';
#Module({
providers: [
{
provide: ConfigService,
useValue: new ConfigService(
`${process.env.NODE_ENV || 'development'}.env`,
),
},
],
exports: [ConfigService],
})
export class ConfigModule {}
I have imported it globally in app.modules as follows
#Module({
imports: [ConfigModule]
})
In my database provider src/database/database.providers.ts I am trying to import the MONGO_URL variable but am getting an error.
// NPM Packages
import * as mongoose from 'mongoose';
// Custom Packages
import { envConfig } from '../config/config.service';
const mongoUrl: string = envConfig.get('MONGO_URI');
export const databaseProviders = [
{
provide: 'DATABASE_CONNECTION',
useFactory: async (): Promise<typeof mongoose> =>
await mongoose.connect(mongoUrl, {
useNewUrlParser: true,
useUnifiedTopology: true,
useCreateIndex: true,
useFindAndModify: false,
}),
},
];
Error:
Property 'get' does not exist on type 'typeof ConfigService'.ts(2339)

Answer 1

Here, you are importing the ConfigService class, not an instance of the ConfigService, so there is no static get method on the ConfigService class, just an instance method. What you can do instead is modify your databaseProvider to look like this:
export const databaseProviders = [
{
provide: 'DATABASE_CONNECTION',
useFactory: async (private readonly configService: ConfigService): Promise<typeof mongoose> =>
await mongoose.connect(configSerivce.get('MONGO_URI'), {
useNewUrlParser: true,
useUnifiedTopology: true,
useCreateIndex: true,
useFindAndModify: false,
}),
inject: [ConfigService],
imports: [ConfigModule]
},
];