Intro To Node: How To Run A File With Node? (Study Note)

What Is Node.js?

According to Node.js, Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. It uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.

from Google Image

Basically, Node.js is a way for us to write JavaScript code on the server side instead of browser or a separate JS file.

Why Should We Know Node.js?

The trendiest IT techonology for people to be learning right now
The largest ecosystem of open source libraries in the world.(From Node.js)
High performance
Write in JavaScript

Interact With Node Console

The Node console is just a place that we can open in our terminal with a simple command, and then we can start typing JavaScript commands. Then, they will be executed just like they are in the browser.

In the Goormide terminal, I type "node", it will automatically switch to node system. Then, I type a simple console.log and enter, it print out the console.log message.

However, Node can't run alert because alert can be only run by browser. Node is a server side where is not a browser. By the way, Document and Listener are not run in Node, too.

Run A File With Node

We can create a JavaScript file named "Test.js" by using Touch command. Then, in this file, we write a simple JavaScript for loop. Basically, when I run the code, it should print out "Hello Test" 10 times.

We want to execute the code in the command line without a browser or HTML or CSS. To use it, we just need to type node and then a file name: node Test.js.

Then, hit enter, it executes the file for us and print the message 10 times.

In the course exercise, the instructor let us to create a new file "echo.js", and then write a echo function inside the file. The function is about to print out the string in certain number of times. For example, echo ("Echo", 10) means print out "Echo" 10 times.

As we save the file and type "node echo.js", the Node runs the code and print out the outcomes.

Comments

Intermediate Express.js: How To Add Styles & Partials in EJS File?

So far, we only have simple HTML tags and ejs tags in each ejs file. Every template page has no style at all. And the basic HTML header and footer are also missing. Today, I learned how to add styles and partials in ejs file. Link Style Step One: Touch a Separate CSS file I create a new directory "Style" under the "EJSDemo" directory, then I add a new CSS file "app.css" inside "Style" folder. Step Two: Add app.use(express.static()) in the app.js I add app.use(express.static("style")) in the "app.js". This will tell Express.js to serve the content of "Style" directory. Step Three: Write styles in CSS file I simple give body an orange background color and set text color to be grey. Step Four: Link to CSS file in the EJS file I just add <link> tag to link the "app.css" file on the top of the h1 tag in each ejs template. As the result, when I run the app and...

Seven Most Common jQuery Methods Last Part: ADD/REMOVE/TOGGLE CLASS()

Add, remove and toggleClass is also a very common way to manipulate style. .addClass() and .removeClass() I add two class selector in the style tag. Class one is to change text color to be green, and class two is change both text and background color. Now I refresh the page and change h1 text to green by using addClass() method: $("h1").addClass("one") . If you want to remove the style, you can change it to removeClass("one"). I do the same thing to the list. I change the list color and add a background color by adding the class two style value: $("li").addClass("two") . .toggleClass() According to jQuery, toggerClass method can add or remove one or more classes from each element in the set of matched elements, depending on either the class's presence or the value of the state argument. I only want to change the first list item color and background by writing: $("li").first().toggleClas...

Intro to Backend: Is Browser The Only Place To Send HTTP Request?

Today, I begin to learn the second part of web develop course: backend. Frontend is the stuff that we can see and interactive with, such as HTML, CSS, and JS. We can type our code, style our page, or write some function to make interaction. However, backend is everything else. For example, we type Target web address in the Internet Browser. As we hit "enter", there are a few steps to go through: 1. The HTTP request is sent to a particular server's IP address. 2. The server figures out what to send us 3. It sends a HTTP response back to us Those process we are hard to see, and it happens in less than one second. The instructor said that the browser is not the only place to send the HTTP request, and there are so many choices out there. In this learning course, we are going to use Postman App . Postman allows us to make HTTP requests and viewer responses. It is really for developers to understand how things are working or debug something. In the P...

Learn Bootcamp From Zero

Search This Blog