Last Sync: 2022-04-30 13:00:04

Programming_Languages/NodeJS/Environments.md

@@ -4,3 +4,38 @@ tags:
   - backend
   - node-js
 ---
+# Environments 
+
+With a full-scale Node application you will typically run three environments:
+* Development
+* Testing
+* Production
+
+### Accessing current Node environment
+ We can control which processes run in a particular environment via the Node envrionment variables: `process.env` (see for instance [ports](./Ports.md)).
+
+To determine the current environment we can use the variable `process.env.NODE_ENV`. This works globally regardless of the kind of Node app we are building. In Express, there is a built in method for retrieving the current envrionment: `app.get('env')`. 
+
+If you haven't manually set up your environments Node will return `undefined` but express defaults to `development`. 
+
+```js
+
+console.log(process.env.NODE_ENV); // undefined
+console.log(app.get("env")); // development
+
+```
+
+Here is an example of setting middleware to run only in the specified environment:
+
+```js
+if (app.get("env") === 'development') {
+  app.use(morgan("common"));
+  console.log('Morgan enabled')
+}
+```
+### Setting the current environment
+We could test that the previous code block works by switching the environment to production. We would do this by setting the environment variable in the terminal:
+
+```
+export NODE_ENV=production
+```

Programming_Languages/NodeJS/Middleware.md

@@ -117,7 +117,6 @@ console.log(app.get("env")); // development
 
 ```
 
-### 
 We can set Morgan to run only in development with:
 
 ```js
@@ -126,3 +125,10 @@ if (app.get("env") === 'development') {
   console.log('Morgan enabled')
 }
 ```
+
+### Setting the current environment
+We could test that the previous code block works by switching the environment to production. We would do this by setting the environment variable in the terminal:
+
+```
+export NODE_ENV=production
+```