feat: add project dotenv friendly

you can now use environment variables

.env.example

@@ -0,0 +1,9 @@
+# values : drv| prod
+APP_ENV = 
+
+# local : 3000 
+PORT = 
+
+# local : mongodb://127.0.0.1:27017
+DB_URL = 
+DB_NAME = 

.gitignore

@@ -1,2 +1,4 @@
 todo.txt
 node_modules
+.env
+.env.dev

config/dotenv.config.js

@@ -0,0 +1,40 @@
+const dotenv = require('dotenv');
+const path = require('path');
+const { env } = require('node:process');
+
+/**
+ * ! define mandatory environment variables inside the envVars array
+ */
+const envVars = ['PORT'];
+
+dotenv.config();
+const ENV_BASE_PATH = path.join(__dirname, '..', `.env.${env.APP_ENV}`);
+dotenv.config({
+	path: ENV_BASE_PATH,
+});
+
+function isEnvVarExits(envVars) {
+	return new Promise((res, rej) => {
+		let notDefinedEnvVars = envVars.filter((envVar) => !env[envVar]);
+		if (notDefinedEnvVars.length > 0)
+			throw {
+				code: 500,
+				error: {
+					message: `following env vars are not defined:\n ${notDefinedEnvVars.join(
+						', ',
+					)}`,
+				},
+			};
+		return res();
+	});
+}
+
+async function runEnv(envVars) {
+	try {
+		let result = await isEnvVarExits(envVars);
+	} catch (error) {
+		process.exit(1);
+	}
+}
+
+runEnv(envVars);

config/mongoose.config.js

@@ -1,8 +1,8 @@
 'use strict';
 const { default: mongoose } = require('mongoose');
+const { env } = require('process');
 
-const DB_NAME = 'jwt';
-const DB_URL = `mongodb://127.0.0.1:27017/${DB_NAME}`;
+const DB_URL = `${env.DB_URL}/${env.DB_NAME}`;
 
 const connectToDb = async (dbUrl) => await mongoose.connect(dbUrl);
 

server.js

@@ -3,12 +3,14 @@ const http = require('http');
 const errorHandler = require('./middlewares/global/errorHandlerMiddleware');
 const notFoundErrorHandler = require('./middlewares/global/notFoundErrorHandler.middleware');
 const router = require('./routes/router');
+const { env } = require('process');
 
+require('./config/dotenv.config');
 require('./config/mongoose.config');
 
 const app = express();
 const server = http.createServer({}, app);
-const PORT = 3000;
+const PORT = env.PORT;
 
 app.use(express.json(), express.urlencoded({ extended: true }));