Training day 12 - JavaScript Basic to Beginners

Heloo people!!

Following notes:

• Installed the Live Server extension on VS code which helps to run the code directly onto the browser.

• Usually we run the JavaScript on Browsers but the introduction of Node made it possible to run it outside of the browser.

//Comments are wriiten like this in JavaScript

• Console.log(“Hello World”) “Hello World” is a string here.

• Separation of Concerns Separate HTML (Structure), CSS (styling), JavaScript (Behaviour) in different files.

• Downloaded Node from node.org.
• Then opened the terminal, opened the project folder and used the following command.node index.jsIt printed “Hello World”.This was my code in index.jsconsole.log(“Hello World”);We did the above to test node and how we can run the Javascript without using browser using Node. But we won’t be learning node in this course.

• Variable names rules //Cannot be a reserved keyword //variable names should be meaningful //Cannot start with a number //Cannot contain space or hyphen(-)

• Value of a constant doesn’t change. We use the keyword const to define a constant.

• Primitive Data TypesStringNumberBooleanUndefined null
• Reference Data TypeObjectsArraysFunctions

Object syntaxlet person = { name: ‘abc’, age: 20 };

Dot Notation to access or change a property: person.name = ‘John’; console.log(person.name);

Bracket Notation person[‘name’]=‘Mary’;

Dynamicallylet selection = ‘name’; person[selection] = ‘Mary’;

Arrays let selectedColors = [‘red’, ‘blue’];

Functions function greet(name) { console.log(‘Hello ’ + name); } greet(‘Sahib’);

‘Sahib’ is an argument and name is a parameter.

Two Types of Functions:- User Defined

• Built-in

Then I learned about Operators.

Strict Equality (Type + Value) Console.log(1 === 1) //true console.log(‘1’ === 1)//false

Lose Equality (Value) console.log(1 == 1) //true console.log(‘1’ == 1) //true

• Ternary Operator
• Logical Operators

false || true answer is true If we have false || ‘Sahib’ answer is ‘Sahib’

// Falsy (false) // undefined // null // 0 // false // ‘’ // NaN

// Anything that is not False is Truth

false || 1 || 2 When the operand is found that is truth, it is returned - no matter how many Truthy values are on the right. It is called shortcutting.

This can be used in a case like this:let userColor = undefined; let defaultColor = ‘blue’; let currentColor = userColor || defaultColor;

console.log(currentColor); //prints blue

I will continue the rest on Tuesday.

Byeee!