Introduction To JavaScript

JavaScript Language has following characteristics:

Lightweight: Small memory footprint, easy to implement
Interpreted: No compilation, Instructions executed only
Object Oriented: Modeled around objects
First-class functions: Functions used as variables and parameters
Scripting language: Writing instructions for runtime environment

JavaScript is used for

Client side web development

Frameworks: JQuery, AngularJs, React, EServer-side

Server-side web development

Frameworks: NodeJS, Express

Variable declaration and definition

Declaration: Give a name to a variable
Definition: Assign a value to the variable

Equal operations

=: assigning value to a variable (a=30)
==: check the values (doesn't consider types)
===: check the values and types

Functions:

no overloading
functions are objects
functional expression : assign function to variable
anonymous function: function with no name

Array methods

push(value): value is appended to the last position of an array
pop(): last element is removed
shift():first element is removed
unshift(value): values is appended as first element

Other Points

Native JavaScript: Doesn't use any framework
Doesn't associate type with variables
If you declare a variable and not define yet: it has undefined value
type of null in Javascript: object
For all non-zero values variable return as true.
JavaScript is not a class-based language: can add properties to object dynamically
Arrays behave like an object
Arguments: keyword that gets function arguments as list

GitHub Repo: https://github.com/kaosadi17/JavaScript/blob/master/Basics.js

Comments

Object Oriented Programming (OOP)

Object Object is an entity that has state and behavior Class Collection of objects is known as class. There are four main types of OOP concepts Inheritance Object acquire all the properties and behavior of parent object Improve code re-usability Polymorphism One task is performed by different ways Use method overload and override Abstraction Hiding internal details and showing functionality Use abstract class and interfaces Encapsulation Binding code and data into a single unit

Maven

Maven is a software project management and comprehension tool, based on the concept of project object model. Maven Usages Build the code in the development environment (compile the source code, run the test cases and packaging the project) Project management tool Generate reports Dependency management Installation Steps You can install Maven by following below steps . Manual Installation Download Maven binary file Create some environment variables M2_HOME = environment point to maven directory PATH = append Maven path until bin to path variable Using Ubuntu Terminal sudo apt-get install maven To check Maven is successfully installed, issue the following command mvn --version To create a Maven project using Terminal use following steps mkdir myApp cd myApp/ mvn archetype:generate : choose archetype for the project groupId: org.amali.myProject (like package name) artifactId: MavenTestApp (like class name) The...

Model-View-Controller (MVC)

MVC(Model-View-Controller) is a software design pattern.It divided your applications into three components Model: Contain business rules and application Data View: Presentation layer (user interface) Controller: Handles the communication between view and model Objectives of MVC Promote code usability Implement separation of concerns Separate user interface and software logic Web Frameworks That Use MVC There are several web frameworks that use MVC design pattern. Ruby On Rails (Ruby) Angular (JS) Django (Python) Express (JS) Flask (Python) Codeigniter (PHP) Simple UseCase for MVC In this use case scenario, Browser sends information that needs to create Employee Object, and Controller save that information in Model and Update the Employee View. Following Image shows the class diagram for above Scenario. Implementation: https://github.com/kaosadi17/MVC

MyTech

Search This Blog