Node.js is a single threaded language which in background uses multiple threads to execute asynchronous code.

Node.js is fast and efficient because use a single thread:

• Thread-based networking is relatively inefficient,
• Thread-base is very difficult to use.
• Users of Node are free from worries of dead-locking the process, since there are no locks.

Node = Not Single Threaded
Event Loop = Single Threaded

• Multiple Threads run in parallel and this is true of Node.
• The event loop processes events in a single thread concurrently.

Everything in JavaScript runs parallel except your code. Your code executes one thing at a time even when other workers are doing their jobs concurrently.

Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world, but Node.js also has a great API, so please, before searching for something in the NPM repository or on the Internet, search the API.

The Package Manager

Open your terminal and type the following:

Installing a Package Globally

This will install the jshint package globally on your system. We can use it to lint a es6.js file:

We can also install packages locally to a project, as opposed to globally on our system. Create a test folder and open a terminal in that directory. Next type:

Installing a Package Locally

This will create and auto-populate a package.json file in the same folder. Next, use npm to install the lodash package and save it as a project dependency: