Introduction to Node.js¶

What is Node.js?¶

Node.js is an open-source platform that executes Javascript code outside the browser. Node.js is also a popular framework to build websites.

Installing Node.js¶

Windows¶

Check the wikiHow tutorial

Linux¶

1. Type in the terminal:

# For Debian-based Linux
apt install nodejs
# For Red Hat-based Linux
dnf install nodejs

1. Make sure nodejs is installed by checking the version:

nodejs --version
# v14.17.1

Run JavaScript Code¶

1. Type in terminal nodejs.
2. You will be prompted by the nodejs console. You can type Javascript Code in that console.

let myname = "Nawras";
console.log(`Hello ${myname}`);

1. You can see Hello Nawras displayed in the console.
2. Type the following in the console:

let result = (a, b) => a + b;
result(6, 10); // 16

Execute a file¶

1. Create a Javascript file with the name "myfile.js", and type the following in it:

function isValid(password){
    return password ? password.length >= 8 : "Password can NOT be empty";
}
console.log(isValid('12345678'));
console.log(isValid(''));
console.log(isValid('1234'));
console.log(isValid());

1. Run it using nodejs:

nodejs myfile.js

1. You get the following results:

true
Password can NOT be empty
false
Password can NOT be empty

Practice¶

Task 1: Write a code that logs the numbers from 10 to 20 out in the console. Run the file using nodejs.

1. Add the following code to the task1.js file:

for (let i=10; i<=20; i++){
    console.log(i);
}

1. Run the code using nodejs: nodejs task1.js
2. You get the following result:

10
11
12
13
14
15
16
17
18
19
20

Task 2: Write a code that creates an object and prints out that object entries. Run the file using nodejs.

1. Add the following code to the task2.js file:

let myObject = {
    name: "Nawras",
    mark: 0
};

for (let key in myObject){
    console.log(`${key}: ${myObject[key]}`);
}

1. Run the code using nodejs: nodejs task2.js
2. You get the following result:

name: Nawras
mark: 0

Task 3: Write a code that creates a new array and displays its values in the console. Run the file using nodejs.

1. Add the following code to the task3.js file:

let arr = ['first', 'second', 'third'];
for(let item of arr){
    console.log(item);
}

1. Run the code using nodejs: nodejs task3.js
2. You get the following result:

first
second
third