+Node.js is a framework that allows you to run JavaScript as a local application. It is designed to make building servers and other asynchronous apps as easy as possible. In this tutorial, we'll show you how to get up-and-running with Node.js on ev3dev. +
+ +**Before you start, make sure that you have [configured a network connection](/docs/networking/) on +your ev3dev device and have [opened an SSH connection](/docs/tutorials/connecting-to-ev3dev-with-ssh/) to it.** + +## Installing ev3dev-lang (and quick-start) +To install the library which allows you to use ev3dev features, run the following command from your SSH connection: + +```shell +npm install ev3dev-lang +``` + +In all JavaScript files that you write from here forward, include the following line to import the module: +```javascript +var ev3dev = require('ev3dev-lang'); +``` + +For a bit more info on this visit the ev3dev-lang-js [GitHub page](https://github.com/wasabifan/ev3dev-lang-js). + +## Exploring Node.js and ev3dev + +### Picking an editor: Nano + +For this tutorial, we will be using a text editor called `nano`. For more info on how to use nano, check out the [nano cheat sheet](/docs/tutorials/nano-cheat-sheet). Feel free to use a different one if you know what you're doing. + +### Hello world +To start, navigate to a project directory (e.g `~/src/js`) that we can store our files in: + +```shell +mkdir -p ~/src/js && cd ~/src/js +``` + +Create a JavaScript file and open it with `nano test.js`. In the opened editor, add the following code: + +```javascript +console.log('hello world!'); +``` + +If you're using `nano`, refer to the [nano cheat sheet](/docs/tutorials/nano-cheat-sheet/) to learn how to save the file. + +Running `node test.js`should print `hello world!` to the console. If this worked, you are ready to start coding with node! + +### Motors +Let's try running a motor. Plug an EV3 motor into port A, then open `test.js` again and write: + +```javascript +var ev3dev = require('ev3dev-lang'); + +var motor = new ev3dev.Motor('outA'); // create new motor plugged into port A called 'motor' + +motor.runForTime(3000, 500); // run the motor for 3 seconds at 500 degrees/second +``` + +Save the file and run it. Again, you can run the file with `node test.js`. If you get any errors when you try to run this, make sure that your motor is plugged in correctly. + +You can refer to the [motor documentation page](http://wasabifan.github.io/ev3dev-lang-js/classes/_motors_.motor.html) to learn about other things you can do with motors (such as using the `runForever()` and `runToRelativePosition()` methods). + +### Sensors +Plug an EV3 color sensor into port 1, then edit `test.js` again appending this to the bottom: + +```javascript +var sensor = new ev3dev.ColorSensor('in1'); // create new color sensor called 'sensor'. in1 refers to port 1 + +setInterval(function () { + console.log(sensor.reflectedLightIntensity); // log the reflected light percent of the sensor every 300 milliseconds +}, 300) +``` + +If you run your file now, you should see it continuously log the brightness that the sensor is detecting to the console. To stop the code, press Ctrl+C. + +For other sensors, check out the [sensors documentation page](http://wasabifan.github.io/ev3dev-lang-js/modules/_sensors_.html). Every sensor has a set of "properties" that can be read; you should refer to the documentation site to see which properties can be used. + +### Next steps +You've now learned the basics of using Node.js with ev3dev! For info on all supported sensors, motors and other documentation visit the [GitHub page](https://github.com/wasabifan/ev3dev-lang-js) and the [documentation page](http://wasabifan.github.io/ev3dev-lang-js). + +The documentation website has a list of "modules" along the side; click on each to visit the detail page for that module. When looking at the page for a specific class, pay attention to the **methods** and **accessors** (e.g., the large motor has **methods** such as `runForever()` and `runForTime()`, and the color sensor has **accessors** such as `reflectedLightIntensity`and `ambientLightIntensity`). + +The [sensor list](http://docs.ev3dev.org/projects/lego-linux-drivers/en/ev3dev-jessie/sensor_data.html) and the [motor list](http://docs.ev3dev.org/projects/lego-linux-drivers/en/ev3dev-jessie/motor_data.html) are the best place to look to see what you can do with ev3dev. + +Happy coding!