===== Node.js =====

==== Installation ====

== Node.js Server ==
At most follow this tutorial: https://devcenter.heroku.com/articles/node-websockets

  - BUGS: **Foreman** is not found and **Bad file descriptor** error. Solutions: \\ http://jasonwatmore.com/post/2013/11/20/Getting-Foreman-working-on-Windows-7-after-installing-the-Heroku-Toolbelt.aspx


== Hot Code-replacement ==
When the server-code is changes, then the node.js app should be restarted. \\
To achieve hot-code-replacement the node.js app should be run differently: by using the tool **nodemon**.

To install nodemon on server do
<code>sudo npm install -g nodemon</code>

It then should be used as following to start a node.js application named "server.js"
<code>nodemon server.js</code>



==== Heroku ====
Heroku is the hosting, which is able to host node.js apps too!

The howto about deploying the app is here: https://devcenter.heroku.com/articles/getting-started-with-nodejs

=== Heroku Addons ===

Addons have to be explicetely enabled on Heroku. Possible addons are
  * WebSockets
  * MongoDB


== Enabling Websockets ==
How to do that is described here: https://devcenter.heroku.com/articles/node-websockets

== Enabling MongoDb ==
MongoDB is a NoSQL DB.
To use a free Plan from [[https://www.mongohq.com/home|mongohq.com]] 
 - create an account  
 - add your data to the url <code>mongodb://<user>:<password>@troup.mongohq.com:10078/buzznodejs</code>
 - use the library mongoskin as stated [[http://dllhell.net/2011/11/08/on-getting-started-with-node-js-mongodb-and-heroku-on-windows/|here]] <code>npm install mongoskin</code>
 - Here is a short mongoskin syntax describtion: http://www.hacksparrow.com/mongoskin-tutorial-with-examples.html <code> 
// require mongoskin - the mongoDB library
var db = require('mongoskin').db('mongodb://<user>:<password>@troup.mongohq.com:10078/buzznodejs');

//insert some data
db.collection('bands').insert({ name: "guns n' roses", members: ['axl rose', 'slash', 'izzy stradlin', 'matt sorum', 'duff mckagan'], year: 1986 }, function (err, result) {
    if (err) throw err;
    if (result) console.log('added!');
});

// retrieve the collection named 'bands'
db.collection('bands').find().toArray(function (err, result) {
    if (err) throw err;
    console.log(result);
});
</code>



===== npx =====

https://www.freecodecamp.org/news/npm-vs-npx-whats-the-difference/


Sometimes you might want to take a look at a specific package and try out some commands. But you cannot do that without installing the dependencies in your local node_modules folder.

That’s where npx comes in.

<code>

npx @pactflow/swagger-mock-validator@latest <path to oas> <path to pact file>

</code>