chore: Setup dotenv for the express application

packages/backend/.env-example

@@ -0,0 +1 @@
+PORT=3000

packages/backend/package.json

@@ -10,6 +10,7 @@
   },
   "dependencies": {
     "debug": "~2.6.9",
+    "dotenv": "^10.0.0",
     "express": "~4.16.1",
     "http-errors": "~1.6.3",
     "morgan": "~1.9.1"

packages/backend/src/app.ts

@@ -1,3 +1,4 @@
+import appEnv from './config/app-env'
 import createError from 'http-errors';
 import express, { Request, Response, NextFunction } from 'express';
 import logger from 'morgan';
@@ -5,7 +6,7 @@ import logger from 'morgan';
 import indexRouter from './routes/index';
 
 const app = express();
-const port = process.env.PORT || '3000';
+const port = appEnv.port;
 
 app.use(logger('dev'));
 app.use(express.json());
@@ -13,10 +14,6 @@ app.use(express.urlencoded({ extended: false }));
 
 app.use('/', indexRouter);
 
-app.listen(port, () => {
-  return console.log(`Server is listening on ${port}`)
-})
-
 // catch 404 and forward to error handler
 app.use(function(req: Request, res: Response, next: NextFunction) {
   next(createError(404));
@@ -32,3 +29,7 @@ app.use(function(err: any, req: Request, res: Response, _next: NextFunction) {
   res.status(err.status || 500);
   res.render('error');
 });
+
+app.listen(port, () => {
+  return console.log(`Server is listening on ${port}`)
+})

packages/backend/src/config/app-env.ts

@@ -0,0 +1,12 @@
+import * as dotenv from 'dotenv';
+dotenv.config();
+
+type AppEnv = {
+  port: string,
+}
+
+const appEnv: AppEnv = {
+  port: process.env.PORT || '3000',
+}
+
+export default appEnv;

yarn.lock

@@ -5772,6 +5772,11 @@ dotenv@8.2.0:
   resolved "https://registry.yarnpkg.com/dotenv/-/dotenv-8.2.0.tgz#97e619259ada750eea3e4ea3e26bceea5424b16a"
   integrity sha512-8sJ78ElpbDJBHNeBzUbUVLsqKdccaa/BXF1uPTw3GrvQTBgrQrtObr2mUrE38vzYd8cEv+m/JBfDLioYcfXoaw==
 
+dotenv@^10.0.0:
+  version "10.0.0"
+  resolved "https://registry.yarnpkg.com/dotenv/-/dotenv-10.0.0.tgz#3d4227b8fb95f81096cdd2b66653fb2c7085ba81"
+  integrity sha512-rlBi9d8jpv9Sf1klPjNfFAuWDjKLwTIJJ/VxtoTwIR6hnZxcEOQCZg2oIL3MWBYw5GpUDKOEnND7LXTbIpQ03Q==
+
 duplexer3@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/duplexer3/-/duplexer3-0.1.4.tgz#ee01dd1cac0ed3cbc7fdbea37dc0a8f1ce002ce2"