Corey Brooks

Corey Brooks

1566359407

Javascript Objects Tutorial Example

Originally published at https://www.djamware.com

A basic example of Javascript Objects example used by almost every Javascript application or embedded Javascript. Javascript basically is object-oriented programming language just like another programming language. Globally, the object built by a collection of properties or variables or fields that has key and value separated by ":". In real life example, a chair is an object, because it has color, height, width, foot, etc that called properties which every property have its own values.

Every Javascript object's properties have their own types. The type can be other objects or primitive type what do not have properties or method. the primitive types in Javascript are:

  1. string
  2. number
  3. boolean
  4. null
  5. undefined

Javascript primitive values are immutable which means they are unchangeable. Objects in Javascript also can describe as variable or object can contain many variables inside it.

Javascript Objects Properties

A property of an object can describe as the variables attached to the objects. The property of an object can declare with simple dot notation.

objectName.properyName

Be careful to declare an object name, like in Java or other languages, the Javascript name declaration is case sensitive alphabet and numeric.

Now, let's see the example below. We will create an object with the name chair and have properties width (number type), height (number type), color (string type), and model (string type).

var chair = new Object();
chair.width = 200;
chair.height = 400;
chair.color = "black";
chair.type = "wooden";

Another way to describe an object in Javascript, you can see below example.

var chair = { width: 200, height: 400, color: 'black', model: 'wooden' };

If you print this object variable to the browser console as below full example.

<html>
 <head>
  <title>Javascript Objects</title>
 </head>
 <body>
  <script>
   // var chair = new Object();
   // chair.width = 200;
   // chair.height = 400;
   // chair.color = 'black';
   // chair.model = 'wooden';

   var chair = new Object({ width: 200, height: 400, color: ‘black’, model: ‘wooden’ });
   console.log(chair);
  </script>
 </body>
</html>

You will see the output like below.

If the property does not have an initial value, then you will see “undefined” in the console.

chair.model;
console.log(chair.model);

The other way to describe the Javascript properties is using bracket “[]” notation. You can see the example below.

var chair = new Object();
chair[‘width’] = 200;
chair[‘height’] = 400;
chair[‘color’] = ‘black’;
chair[‘model’] = ‘wooden’;

Javascript Objects Method

A method is a function associated with an object or a property that act as a function for the object. Methods are defined as the way normal functions are defined, except that they have to be assigned as the property of an object. Below is the Javascript method structure.

var objectName = {
 method1: function(params) {
  // …do something
 }
 method2: function(params) {
  // …do something
 }
};

or

var objectName = {
 method1(params) {
  // …do something
 }
 method2(params) {
  // …do something
 }
};

or

var objectName.method1 = {
 // …do something
}

Here’s an example including the properties attached to the object.

var car = new Object({
 engine: ‘2000cc’, // property
 brand: ‘Chevrolet’, // property
 model: ‘Aveo’,   // property
 color: ‘Silver’,  // property
 price: 12999,   // property
 startEngine: function(gear) { // Object method 1
  console.log('Engine starting with gear position ’ + gear); // Method body
 },
 stopEngine: function(gear) { // Object method 2
  console.log('Engine stopped with gear position ’ + gear); // Method body
 }
});

car.startEngine(1);
car.stopEngine(4);

Below the declaration of the object is method calls. You also can change the property value of that object.

That it’s, a basic Javascript object. You can get the full source code from our GitHub.

Thanks for reading

If you liked this post, please do share/like it with all of your programming buddies!

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Further reading about JavaScript

The Complete JavaScript Course 2019: Build Real Projects!

Vue JS 2 - The Complete Guide (incl. Vue Router & Vuex)

JavaScript Bootcamp - Build Real World Applications

The Web Developer Bootcamp

JavaScript Programming Tutorial - Full JavaScript Course for Beginners

New ES2019 Features Every JavaScript Developer Should Know

Best JavaScript Frameworks, Libraries and Tools to Use in 2019

JavaScript Basics Before You Learn React

Build a CMS with Laravel and Vue

Google’s Go Essentials For Node.js / JavaScript Developers

7 best JavaScript Design Patterns You Should Know

12 Concepts That Will Level Up Your JavaScript Skills

React vs Angular vs Vue.js by Example


#javascript #objective-c #web-development

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Javascript Objects Tutorial Example
Arvel  Parker

Arvel Parker

1591611780

How to Find Ulimit For user on Linux

How can I find the correct ulimit values for a user account or process on Linux systems?

For proper operation, we must ensure that the correct ulimit values set after installing various software. The Linux system provides means of restricting the number of resources that can be used. Limits set for each Linux user account. However, system limits are applied separately to each process that is running for that user too. For example, if certain thresholds are too low, the system might not be able to server web pages using Nginx/Apache or PHP/Python app. System resource limits viewed or set with the NA command. Let us see how to use the ulimit that provides control over the resources available to the shell and processes.

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

MEAN Stack Tutorial MongoDB ExpressJS AngularJS NodeJS

We are going to build a full stack Todo App using the MEAN (MongoDB, ExpressJS, AngularJS and NodeJS). This is the last part of three-post series tutorial.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II)
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III) 👈 you are here
Before completing the app, let’s cover some background about the this stack. If you rather jump to the hands-on part click here to get started.

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

Creating RESTful APIs with NodeJS and MongoDB Tutorial

Welcome to this tutorial about RESTful API using Node.js (Express.js) and MongoDB (mongoose)! We are going to learn how to install and use each component individually and then proceed to create a RESTful API.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II) 👈 you are here
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III)

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

Yoshiko  Jones

Yoshiko Jones

1598195340

How to configure AWS SES with Postfix MTA

How do I configure Amazon SES With Postfix mail server to send email under a CentOS/RHEL/Fedora/Ubuntu/Debian Linux server?

Amazon Simple Email Service (SES) is a hosted email service for you to send and receive email using your email addresses and domains. Typically SES used for sending bulk email or routing emails without hosting MTA. We can use Perl/Python/PHP APIs to send an email via SES. Another option is to configure Linux or Unix box running Postfix to route all outgoing emails via SES.

  • » Remove sendmail
  • » Install postfix
  • » Configuring postfix for SES
  • » Test postfix

Procedure to configure AWS SES with Postfix

Before getting started with Amazon SES and Postfix, you need to sign up for AWS, including SES. You need to verify your email address and other settings. Make sure you create a user for SES access and download credentials too.

Step 1 – Uninstall Sendmail if installed

If sendmail installed remove it. Debian/Ubuntu Linux user type the following apt command/apt-get command:

$`` sudo apt --purge remove sendmail

CentOS/RHEL user type the following yum command or dnf command on Fedora/CentOS/RHEL 8.x:

$`` sudo yum remove sendmail

$`` sudo dnf remove sendmail

Sample outputs from CentOS 8 server:

Dependencies resolved.
===============================================================================
 Package           Architecture  Version               Repository         Size
===============================================================================
Removing:
 sendmail          x86_64        8.15.2-32.el8         @AppStream        2.4 M
Removing unused dependencies:
 cyrus-sasl        x86_64        2.1.27-1.el8          @BaseOS           160 k
 procmail          x86_64        3.22-47.el8           @AppStream        369 k

Transaction Summary
===============================================================================
Remove  3 Packages

Freed space: 2.9 M
Is this ok [y/N]: y

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

Tyrique  Littel

Tyrique Littel

1597723200

FreeBSD s3cmd failed [SSL CERTIFICATE_VERIFY_FAILED]

When I install s3cmd package on my FreeBSD system and try to use the s3cmd command I get the following error:

_ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (ssl.c:1091)

How do I fix this problem on FreeBSD Unix system?

Amazon Simple Storage Service (s3 ) is object storage through a web service interface or API. You can store all sorts of files. FreeBSD is free and open-source operating systems. s3cmd is a command-line utility for the Unix-like system to upload, download files to AWS S3 service from the command line.

ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed error and solution

This error indicates that you don’t have packages correctly installed, especially SSL certificates. Let us see how to fix this problem and install s3cmd correctly on FreeBSD to get rid of the problem.

How to install s3cmd on FreeBSD

Search for s3cmd package:

$ pkg search s3cmd

Execute the following command and make sure you install Python 3.x package as Python 2 will be removed after 2020:

$ sudo pkg install py37-s3cmd-2.1.0

Updating FreeBSD repository catalogue...
FreeBSD repository is up to date.
All repositories are up to date.
Checking integrity... done (0 conflicting)
The following 8 package(s) will be affected (of 0 checked):

New packages to be INSTALLED:
	libffi: 3.2.1_3
	py37-dateutil: 2.8.1
	py37-magic: 5.38
	py37-s3cmd: 2.1.0
	py37-setuptools: 44.0.0
	py37-six: 1.14.0
	python37: 3.7.8
	readline: 8.0.4

Number of packages to be installed: 8

The process will require 118 MiB more space.

Proceed with this action? [y/N]: y
[rsnapshot] [1/8] Installing readline-8.0.4...
[rsnapshot] [1/8] Extracting readline-8.0.4: 100%
[rsnapshot] [2/8] Installing libffi-3.2.1_3...
....
..
[rsnapshot] [8/8] Extracting py37-s3cmd-2.1.0: 100%
=====
Message from python37-3.7.8:

--
Note that some standard Python modules are provided as separate ports
as they require additional dependencies. They are available as:

py37-gdbm       databases/py-gdbm@py37
py37-sqlite3    databases/py-sqlite3@py37
py37-tkinter    x11-toolkits/py-tkinter@py37

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